Organometallic Study Meeting#11 Chapter 5. Ligand Substitution Reactions
|
|
|
- Reginald Shepherd
- 5 years ago
- Views:
Transcription
1 rganometallic Study eeting#11 Chapter 5. igand Substitution Reactions 5.1 Introdution 011/6/18 K.isaki igand Substitution = A reaction in which a free ligand replaces a coordinated ligand Dissociative echanism S 1reaction <Interchange echanism> Associative echanism S reaction n n-1 n-1 n n-1 rds n-1 coordinatively unsaturated metal - is longer Dessociative interchange TS Associative interchange -' is longer partial bonding transition state 18e - type of complex 16e - or17e - 0thorderin 1st order overall smallpositive S smallpositive V more e-rich metal more e-poor metal sterically hindered metal affected strongly bythestrengthof-bond reduction weakens - bond (acceleration) rate law activation parameters favorable electronic& steric factors others 1storderin nd order overall largenegative S largenegative V morebasic more e-poor metal sterically accessible metal 5.. Thermochemical Considerations n + n-1 + BDE(-) > BDE(-) thermodynamically favorable BDE = bond dissociation energy energy needed for homolytic cleavage(two radical generation) for charged -type ligand energy needed for heterolytic cleavage(unsaturated metal + ewis base) for neutral -type ligand cf) BDE(-C)= 5-46kcal/mol = o Cheatingleadstocleave BDE(C 3 -C 3 )=88kcal/mol BDE(C 3 -)=104kcal/mol cf) BDE(polyhapto) > BDE(monohapto) cf) BDE(-)tendtobefirst-row<second-row<third-row(butnotalways) BDE(Cr(C) 5 -C) <BDE(o(C) 5 -C) < BDE(W(C) 5 -C) kcal/mol cf) BDE(- acidic)>bde(- neutral)ifislowvalent cf) BDE(less hindered) > BDE(more hindered)
2 5.3. echanisms of igand Substitutions of 16e- and 17e- complexes >Associativemechanismsofsquare-planerd 8 complexes #"solvent assistance" = two associative substitution rate=k obs [ 3 ] = (k 1 +k [])[ 3 ] scheme5./figure5.1 solvent assisted path non-solvent assisted path often occurs in parallel #stereochemistry=retentive(butnotalways) //analogyofs c t c c t c c t c c t c - c t c # other factors affecting to rate softness nucleophilicity Cl if pentacoordinate intermediate is long-lived, stereochemistry is lost via Berry pseudorotation. Cl P 3 >>SC - >>I -,Br - > 3 - >Cl - > - ~ 3 Cl leaving ability + BDE o-tol PEt 3 Et 3 P Cl 3 - > >Cl - >Br - >I - > 3 - >SC - > - >C - (butlessdominantthaneffectof) i>pd> o-tol PEt 3 Et 3 P trans effect = trans ligand affect the rate of ligand substitutions = transition state/dynamism/kinetic ( trans infulence = related to bond length = ground state/structure/thermodynamic) - >e - > - >Cl - t PEt 3 Et 3 P Cl spansafactorof x10 4 t PEt 3 Et 3 P cis effect = similar effect by cis ligand, but usually smaller contribution Et 3 P PEt 3 c Cl PEt 3 c Fig 5. e - > - >Cl - spansafactorof x3 largerwhen t is -donating(weakens-bond),or -accepting(stabilizing5-coordinateintermediate).
3 >Whendessociativemechanismofsquare-planerd 8 complexesisdominant? #weaklybound # strong trans influence ligand # unsaturated metal site is covered by polydentate coordination # axial association of is prohibited # metal geometry is distorted from square planer # coordination number > 4 # very fast association generate super leaving group S S strong trans influence R P t Bu Ir DS-d o C S covered vacant site R P t Bu Ir S S CD 3 CD 3 esi esi distoted geometry Pe Pe P t Bu strong trans influence P t Bu strong trans influence e e DTf fast D e e D e e dessociative exchange > Associative mechenism of 17e- complexes substitution rate: 17e complexes > 18e complexes associative mech. leads to energetic gains. ) Poe's experiment ref) Re (C) 10 h Re(C) 5 17e P 3 CCl 4 Dessociative mech. Re(C) 4 Cl P 16e 3 C Re(C) 4 (P 3 )Cl+ Re(C) 5 C 18e l 18e Fig. 5.3 P 3 Re(C) 5 (P 3 ) C CCl 4 Re(C) 4 (P 3 ) 19e Associative mech. 17e excesschadnoeffectontheratio dessociative path was denied R affects reaction rate V(C) 6 PR 3 V(C) 5 (PR 3 ) 17e hexane, rt rate=k[v(c) 6 ][PR 3 ] negative S
4 5.4. echanisms of igand Substitutions of 18e- complexes > Dessociative mechanism k 1 k n - k -1 n n - rate= k 1 k [ n ][] k -1 []+k [] k 1 [ n ] fig 5.4 (usuallyk []>>k -1 []) i(c) 4 C solvent i(c) 3 (solv) i(c) 3 BDE((C) 3 i-c)=5kcal/mol positive S (=+8~+13eu) # Steric bulkiness of ligand(tolman's cone angle) largely affects the rate. R=Et<<p-tol< i Pr<o-tol<<P 3 K D i(p(r) 3 ) 4 i(p(r) 3 ) 3 + P(R) 3, rt #stereochemistry=easilylost//analogytos 1 18e - 18e - - flipof16e - intermediate pseudorotation # cis effect in(pseudo)octahedral complexes =makesdessociationof cis fasterthanthatof trans c c c c t t c c c c c t c c c - 3 >Ac - -,C, RC() - >R>S - >R>Cl - >Br - >I - >carbene>p 3 > -,C larger in case of chelating, -donating, less -donating ligand stablization of unsaturated metal C C C W C Ac C 13 C C C C W C 13 C Ac
5 > Reagent and catalyst induced dessociation of C # photo-induced # redox, SET-induced Re(C) 5 h PBu 3 Re(C) 4 (PBu 3 ) rt,0min n *(-) analogous to radical chain rxn w/olight:rat75 o Cfor60days scheme 5.8 # ligand oxidation-induced (review: Coord. Chem. Rev. 1984, 53, 7.) (C) -oxide promoted Pauson-Khand rxn(schreiber, S.. et al. T 1990, 31, 589) x R 3 - R 3 (C) x-1 (C) x-1 (R 3 ) + C (faster if C is more electrophilic)
6 5.4. echanisms of Substitutions Involving Polyhapto igands >DieneandTriene # 18e- complex + strong dative = competitive pathways rate=(k 1 +k [])[(C 4 )(diene)] Fig5,43 dissociative path associative path >Arene # stepwiseringslip( )occurs on the occasion when solvent or ligand income. faster in case of donar solvent, weakly bindin arenes cyclohexanone(1300) > C(600) > TF(30) ~ Cr(C) 3 (C 6 e 6 )(30) >uncatalyzed(1) scheme 5.9 stability # photoirradiation, redox, SET also accelerate the process. ) acceleration by ligand design(semmelhack,. F. et al. JACS 001,13, 8438, JACS 005, 17, 7759.) <concept> = -acidic ligand (comparable to C)
7 >Cpligand # associative substitution of ligand other than Cp ring stepwiseringslip( 5-3 )occursonthe occasion when solvent or ligand income. scheme 5.48 Fig.5.7 Table 5.11 aromaticity is not preserved during ring slip, in case of rightside Cp families. asotherratioinalization,groundstateenergyof 5 -indenylishigher(becauseofringdissymmetry)than 5 -Cp. 5.6 igand Substitutions in ultimetallic Clusters All associative, dessociative, reagent-induced subsitutions are allowed as mononuclear complexes. > Complex possessing metal-metal bond (C) 4 (C) 4 (C) 4 associative pathway (see17e - complex) -C (C) 4 (C) 3 dessociative pathway (see18e - complex) depends relative strength between BDE(-) and BDE(-C) weaker in case of first-row transition metals ) eq st: associative nd: dessociative 3rd: dessociative relativerate,1st:nd:3rd =1:30:90 presence of bridging C ligand affects largely.
Organometallic Rections 1: Reactions at the Metal
E Organometallic Rections 1: Reactions at the Metal Three major classes of reactions: 1 Ligand Substitution associative (cf. S N 2) dissociative (cf. S N 1) interchange (not dealt with in this course)
Chapter 21 Coordination chemistry: reactions of complexes
CHEM 511 chapter 21 page 1 of 7 Chapter 21 Coordination chemistry: reactions of complexes Reactions of Complexes Typically measure ligand substitution reactions in solution (usually water) Lability and
Reaction Mechanisms - Ligand Substitutions. ML n-x P x + xl
Reaction chanisms - igand Substitutions igand Substitutions 1 A substitution reaction is one in which an existing ligand on a metal center is replaced by another ligand. Exactly how this occurs depends
Chem 634. Introduction to Transition Metal Catalysis. Reading: Heg Ch 1 2 CS-B 7.1, , 11.3 Grossman Ch 6
Chem 634 Introduction to Transition etal Catalysis eading: eg Ch 1 2 CS-B 7.1, 8.2 8.3, 11.3 Grossman Ch 6 Announcements Problem Set 1 due Thurs, 9/24 at beginning of class ffice our: Wed, 10:30-12, 220
An Overview of Organic Reactions. Reaction types: Classification by outcome Most reactions produce changes in the functional group of the reactants:
An Overview of Organic Reactions Reaction types: Classification by outcome Most reactions produce changes in the functional group of the reactants: 1. Addition (forward) Gain of atoms across a bond Example:
Organometallic Chemistry and Homogeneous Catalysis
rganometallic hemistry and omogeneous atalysis Dr. Alexey Zazybin Lecture N8 Kashiwa ampus, December 11, 2009 Types of reactions in the coordination sphere of T 3. Reductive elimination X-L n -Y L n +
Kinetics and reaction mechanisms in coordination compounds
Kinetics and reaction mechanisms in coordination compounds Square planar complexes Three pathways by which one ligand can replace another Nucleophilic substitutions in square planar complexes (with Y being
Chapter 2 The Elementary Steps in TM Catalysis
hapter 2 The Elementary Steps in TM atalysis + + ligand exchange A oxidative addition > n + A B n+2 reductive elimination < B n n+2 oxidative coupling + M' + M' transmetallation migratory insertion > (carbo-,
Elementary Organometallic Reactions
Elementary eactions CE 966 (Tunge) Elementary rganometallic eactions All mechanisms are simply a combination of elementary reactions. 1) Coordination -- issociation 2) xidative Addition -- eductive Elimination
5.03, Inorganic Chemistry Prof. Daniel G. Nocera Lecture 15 Apr 11: Substitution Reactions and the Trans Effect
5.03, Inorganic Chemistry Prof. Daniel G. ocera Lecture 15 Apr 11: Substitution Reactions and the Trans Effect A substitution reaction is one in which an existing ligand on a metal center is replaced by
A Summary of Organometallic Chemistry
A Summary of Organometallic Chemistry Counting valence electrons (v.e.) with the ionic model 1. Look at the total charge of the complex Ph 3 P Cl Rh Ph 3 P PPh 3 OC CO 2 Fe OC CO Co + charge:0 charge:
Substitution and Elimination reactions
PART 3 Substitution and Elimination reactions Chapter 8. Substitution reactions of RX 9. Elimination reactions of RX 10. Substit n/elimin n of other comp ds 11. Organometallic comp ds 12. Radical reactions
Insertion Reactions. 1) 1,1 insertion in which the metal and the X ligand end up bound to the same (1,1) atom
Insertion Reactions xidative addition and substitution allow us to assemble 1e and 2e ligands on the metal, respectively. With insertion, and its reverse reaction, elimination, we can now combine and transform
Metal Hydrides, Alkyls, Aryls, and their Reactions
Metal Hydrides, Alkyls, Aryls, and their Reactions A Primer on MO Theory σ-bonding in Organotransition Metal Complexes M-C Bond Energies in Organotransition Metal Complexes Thermodynamic Predictions
Some Hartwig Chemistry Experimental Approaches and Detailed Mechanistic Analysis
Some artwig Chemistry Experimental Approaches and Detailed chanistic Analysis b. 1964 1986 A.B. Princeton U, Maitland Jones 1990.D. UC Berkeley, obert Bergman and ichard Anderson 1990-92 Post-doc, MIT,
Radical Reactions. Radical Stability!!! bond dissociation energies X Y X + Y. bond BDE (kcal/mol) bond BDE (kcal/mol) CH 3 CH 3 CH 2 95 O H R 2 C H
adical eactions adical Stability!!! bond dissociation energies X Y X Y bond BDE (kcal/mol) bond BDE (kcal/mol) C 3 104 108 C 3 C 2 98 110 95 2 C 102 (-) 93 (C-) 92 C 3 C 3 36 89 85 C 3 C 3 80 adical eactions
Organometallic Study Meeting Chapter 17. Catalytic Carbonylation
rganometallic Study Meeting Chapter 17. Catalytic Carbonylation 17.1 verview C or 3 3 C 3 C C 3 horrcat. Ar-X or alkene ' d cat. 2011/10/6 K.isaki or ' or N n 2 1 alkene, 2 Coorhcat. d cat. alkene C carbon
Oxidative Addition/Reductive Elimination 1. Oxidative Addition
Oxidative Addition Oxidative Addition/Reductive Elimination 1 An oxidative addition reaction is one in which (usually) a neutral ligand adds to a metal center and in doing so oxidizes the metal, typically
Effect of nucleophile on reaction
1 Effect of nucleophile on reaction X DS c X c c X DS c + X cleophile not involved in DS of S N 1 so does not effect the reaction (well obviously it controls the formula of the product!) cleophile has
CHAPTER 7. Further Reactions of Haloalkanes: Unimolecular Substitution and Pathways of Elimination
CHAPTER 7 Further Reactions of Haloalkanes: Unimolecular Substitution and Pathways of Elimination 7-1 Solvolysis of Tertiary and Secondary Haloalkanes The rate of S N 2 reactions decrease dramatically
REACTION AND SYNTHESIS REVIEW
REACTION AND SYNTHESIS REVIEW A STUDENT SHOULD BE ABLE TO PREDICT PRODUCTS, IDENTIFY REACTANTS, GIVE REACTION CONDITIONS, PROPOSE SYNTHESES, AND PROPOSE MECHANISMS (AS LISTED BELOW). REVIEW THE MECHANISM
Recapping where we are so far
Recapping where we are so far Valence bond constructions, valence, valence electron counting, formal charges, etc Equivalent neutral classification and MLX plots Basic concepts for mechanism and kinetics
Lecture Notes Chem 51B S. King I. Conjugation
Lecture Notes Chem 51B S. King Chapter 16 Conjugation, Resonance, and Dienes I. Conjugation Conjugation occurs whenever p-orbitals can overlap on three or more adjacent atoms. Conjugated systems are more
O CH 3. Mn CH 3 OC C. 16eelimination
igratory Insertion igratory Insertion/Elimination 1 A migratory insertion reaction is when a cisoidal anionic and neutral ligand on a metal complex couple together to generate a new coordinated anionic
Advanced Inorganic Chemistry. Alireza Gorji Department of Chemistry, Yazd University. Introduction.
Advanced Inorganic Chemistry Alireza Gorji Department of Chemistry, Yazd University Introduction 2 1 Kinetics vs. Thermodynamics Thermodynamics Kinetics G = H -T S G = H -T S G = -RTlnK G= -RTlnk Large
Organic Chemistry CHM 314 Dr. Laurie S. Starkey, Cal Poly Pomona Alkyl Halides: Substitution Reactions - Chapter 6 (Wade)
rganic Chemistry CM 314 Dr. Laurie S. Starkey, Cal Poly Pomona Alkyl alides: Substitution Reactions - Chapter 6 (Wade) Chapter utline I. Intro to RX (6-1 - 6-7) II. Substitution Reactions A) S N 2 (6-8,
Electrophilic Carbenes
Electrophilic Carbenes The reaction of so-called stabilized diazo compounds with late transition metals produces a metal carbene intermediate that is electrophilic. The most common catalysts are Cu(I)
sp 3 C-H insertion by α-oxo Gold Carbene B4 Kei Ito
1 sp 3 C-H insertion by α-oxo Gold Carbene B4 Kei Ito 2016. 1. 30 1. Introduction 2 About Carbene 3 Brief history of carbene (~2000) Carbene Neutral compounds featuring a divalent carbon atom with only
Nuggets of Knowledge for Chapter 17 Dienes and Aromaticity Chem 2320
Nuggets of Knowledge for Chapter 17 Dienes and Aromaticity Chem 2320 I. Isolated, cumulated, and conjugated dienes A diene is any compound with two or C=C's is a diene. Compounds containing more than two
The Study of Chemical Reactions. Mechanism: The complete, step by step description of exactly which bonds are broken, formed, and in which order.
The Study of Chemical Reactions Mechanism: The complete, step by step description of exactly which bonds are broken, formed, and in which order. Thermodynamics: The study of the energy changes that accompany
Chiral Catalyst II. Palladium Catalysed Allylic Displacement ( -allyl complexes) 1. L n Pd(0) 2. Nuc
Chiral Catalyst II ast lecture we looked at asymmetric catalysis for oxidation and reduction Many other organic transformations, this has led to much investigation Today we will look at some others...
Chapter 11, Part 1: Polar substitution reactions involving alkyl halides
hapter 11, Part 1: Polar substitution reactions involving alkyl halides Overview: The nature of alkyl halides and other groups with electrophilic sp 3 hybridized leads them to react with nucleophiles and
Química Orgânica I. Organic Reactions
Química Orgânica I 2008/09 w3.ualg.pt\~abrigas QOI 0809 A6 1 Organic Reactions Addition two molecules combine Elimination one molecule splits Substitution parts from two molecules exchange Rearrangement
1. Addition of HBr to alkenes
eactions of Alkenes I eading: Wade chapter 8, sections 8-1- 8-8 tudy Problems: 8-47, 8-48, 8-55, 8-66, 8-67, 8-70 Key Concepts and kills: Predict the products of additions to alkenes, including regiochemistry
Problem session (3) Daiki Kuwana. Please fill in the blank and explain reaction mechanisms and stereoselectivities.
Problem session (3) Daiki Kuwana Please fill in the blank and explain reaction mechanisms and stereoselectivities. 1. 1-1 1. (Ac) 2 (10 mol%), DPEphos (20 mol%) Et 3, toluene, 90 C 2. s 4 (14 mol%), M;
What is the major product of the following reaction?
What is the major product of the following reaction? Predict the major product of the following reaction: 2-methylbutane + Br 2 /light energy? A) 1-bromo-2-methylbutane B) 2-bromo-2-methylbutane C) 2-bromo-3-methylbutane
The carbon-carbon double bond is the distinguishing feature of alkenes.
Alkenes: Structure & Properties Alkane (acyclic): n 2n+2 > saturated. Alkene (acyclic): n 2n > unsaturated. eg ethylene (IUPA: ethene), 2 4 : 2 = 2 The carbon-carbon double bond is the distinguishing feature
Chap. 8 Substitution Reactions
Chap. 8 Substitution Reactions Y + R X R' Y + X Nucleophilic not necessarily the same as R Electrophilic S N 1 slow (C 3 ) 3 CCl (C + Cl - 3 ) 3 C + (C 3 ) 3 C + OC 2 C 3 C 3 C 2 O C 3 C 2 O d[( C ) 3CCl]
Course 201N 1 st Semester Inorganic Chemistry Instructor: Jitendra K. Bera
andout-9 ourse 201N 1 st Semester 2006-2007 Inorganic hemistry Instructor: Jitendra K. Bera ontents 3. rganometallic hemistry xidative Addition, Reductive Elimination, Migratory Insertion, Elimination
σ Bonded ligands: Transition Metal Alkyls and Hydrides
σ Bonded ligands: Transition Metal Alkyls and Hydrides Simplest of organo-transitionmetal species Rare until and understanding of their stability in the 60 s and 70 s Metal alkyls can be considered as
Classification of Reactions by:
lassification of Reactions by: 1) Functional group 2) Kind a) Addition: A + B > b) Elimination: A > B + c) Substitution: A-B + -D > A- + B-D d) Rearrangement: A > B, where B is a constitutional isomer
+ + CH 11: Substitution and Elimination Substitution reactions
C 11: Substitution and Elimination Substitution reactions Things to sort out: Nucleophile Electrophile -- > substrate Leaving Group S N 2 S N 1 E 1 E 2 Analysis Scheme Kinetics Reaction profile Substrates
C h a p t e r S e v e n : Substitution Reactions S N 2 O H H H O H H. Br -
C h a p t e r S e v e n : Substitution Reactions Br Br S N 2 CM 321: Summary of Important Concepts YConcepts for Chapter 7: Substitution Reactions I. Nomenclature of alkyl halides, R X A. Common name:
Inorganic Chemistry with Doc M. Fall Semester, 2012 Day 21. Transition Metals Complexes V: Reaction Mechanisms
Inorganic Chemistry with Doc M. Fall Semester, 2012 Day 21. Transition Metals Complexes V: Reaction Mechanisms Name(s): Element: Topics: 1. Substitution reactions: dissociative v. associative 4. Pseudorotation
Conjugated Systems, Orbital Symmetry and UV Spectroscopy
Conjugated Systems, Orbital Symmetry and UV Spectroscopy Introduction There are several possible arrangements for a molecule which contains two double bonds (diene): Isolated: (two or more single bonds
Only five of the molecules below may be prepared as the sole product of allylic halogenation of the respective alkene. Circle those five.
Chem 232 D. J. Wardrop wardropd@uic.edu Problem Set 6 Answers Question 1. nly five of the molecules below may be prepared as the sole product of allylic halogenation of the respective alkene. Circle those
Strained Molecules in Organic Synthesis
Strained Molecules in rganic Synthesis 0. Introduction ~ featuring on three-membered rings ~ Tatsuya itabaru (M) Lit. Seminar 08068 for cyclobutadienes : see Mr. Yamatsugu's Lit. Sem. 069 eat of Formation
Sonogashira: in situ, metal assisted deprotonation
M.C. White, Chem 253 Cross-Coupling -120- Week of ctober 11, 2004 Sonogashira: in situ, metal assisted deprotonation catalytic cycle: ' (h 3 ) n d II The first report: h Sonogashira T 1975 (50) 4467. h
c. Cl H Page 1 of 7 major P (E > Z and more substituted over less substituted alkene) LG must be axial are the same Cl -
CEM 109A 1. Predict the products of the following reactions (a-c E2, d-f E1 KEY focuses only on elimination products, in most cases there will also be substitution products.) a. - LG must be axial - are
Preparation of Alkyl Halides, R-X. Reaction of alkanes with Cl 2 & Br 2 (F 2 is too reactive, I 2 is unreactive): R + X X 2.
Preparation of Alkyl alides, R-X Reaction of alkanes with Cl 2 & Br 2 (F 2 is too reactive, I 2 is unreactive): UV R + X 2 R X or heat + X This mechanism involves a free radical chain reaction. A chain
(1) Solvent interactions Water is a ligand itself so it can become involved in the chemistry: Overall reaction: [L 5 MX] + Y [L 5 MY] + X
![(1) Solvent interactions Water is a ligand itself so it can become involved in the chemistry: Overall reaction: [L 5 MX] + Y [L 5 MY] + X](/thumbs/75/72042422.jpg "(1) Solvent interactions Water is a ligand itself so it can become involved in the chemistry: Overall reaction: [L 5 MX] + Y [L 5 MY] + X")
(1) Solvent interactions Water is a ligand itself so it can become involved in the chemistry: Overall reaction: [L 5 MX] + Y [L 5 MY] + X 270 1.(slow) [L 5 MX] + H 2 O [L 5 M(H 2 O)] + X 2. (fast) [L 5
Chapter 8. Substitution reactions of Alkyl Halides
Chapter 8. Substitution reactions of Alkyl Halides There are two types of possible reaction in organic compounds in which sp 3 carbon is bonded to an electronegative atom or group (ex, halides) 1. Substitution
Organic Electron Donors
rganic Electron onors Yang Li Zakarian esearch Group epartment of Chemistry and Biochemistry University of California, anta Barbara 11/15/2018 2 2 2 2 2 2 TAF1 TAE TAF2 TTF BPL utlines rganic Electron
Elimination Reactions. Chapter 6 1
Elimination Reactions Chapter 6 1 E1 Mechanism Step 1: halide ion leaves, forming a carbocation. Step 2: Base abstracts H + from adjacent carbon forming the double bond. Chapter 6 2 E1 Energy Diagram E1:
CHEM 231 (Davis) Organic Chemistry FINAL EXAM May 15, YOUR NAME (Last, First, M.I.) DISCUSSION SECTION #53 (5 Points)
CHEM 231 (Davis) rganic Chemistry FINAL EXAM May 15, 2006 YUR NAME (Last, First, M.I.) DISCUSSIN SECTIN #53 (5 Points) Initial of last name Instructions Please fill in your name in the space above and
Module 10 : Reaction mechanism. Lecture 1 : Oxidative addition and Reductive elimination. Objectives. In this lecture you will learn the following
Module 10 : Reaction mechanism Lecture 1 : Oxidative addition and Reductive elimination Objectives In this lecture you will learn the following The oxidative addition reactions. The reductive elimination
Reaction chemistry of complexes Three general forms: 1. Reactions involving the gain and loss of ligands a. Ligand Dissoc. and Assoc. (Bala) b.
eaction chemistry of complexes Three general forms: 1. eactions involving the gain and loss of ligands a. Ligand Dissoc. and Assoc. (Bala) b. Oxidative Addition c. eductive Elimination d. Nucleophillic
COURSE OBJECTIVES / OUTCOMES / COMPETENCIES.
COURSE OBJECTIVES / OUTCOMES / COMPETENCIES. By the end of the course, students should be able to do the following: See Test1-4 Objectives/Competencies as listed in the syllabus and on the main course
Organometallic Catalysis
Organometallic Catalysis The catalysts we will study are termed homogeneous catalysts as they are dissolved in th e same solvent as the substrate. In contrast, heterogeneous catalysts, such as palladium
Benzene and Aromatic Compounds. Chapter 15 Organic Chemistry, 8 th Edition John McMurry
Benzene and Aromatic Compounds Chapter 15 Organic Chemistry, 8 th Edition John McMurry 1 Background Benzene (C 6 H 6 ) is the simplest aromatic hydrocarbon (or arene). Four degrees of unsaturation. It
Repeated insertion. Multiple insertion leads to dimerization, oligomerization or polymerization. κ 1: mainly dimerization κ
Repeated insertion ultiple insertion leads to dimerization, oligomerization or polymerization. k prop Et Key factor: k CT / k prop = κ κ 1: mainly dimerization κ 0.1-1.0: oligomerization (always mixtures)
The following molecules are related:
Isolobal Analogy Inclusion of the ligand η-c 5 H 5 - which, as a donor of 3 π-electron pairs formally occupies 3 coordination sites, yields the analogies: The following molecules are related: 1 Isolobal
Hydrides and Dihydrogen as Ligands: Lessons from Organometallic Chemistry. Lecture 9
ydrides and Dihydrogen as Ligands: Lessons from Organometallic Chemistry Lecture 9 Inorganic Chemistry Chapter 1: Figure 10.1 2009 W.. Freeman Synthesis of Organometallic Complex ydrides Reaction of MCO
How alkyl halides react
Chapter 10 1 How alkyl halides react δ+ δ- RCH 2 -X X= halogen X = higher EN C = lower EN This polar carbon-halogen bond causes alkyl halide to undergo S N and elimination reaction. 2 The mechanism of
10/26/2010. An Example of a Polar Reaction: Addition of H 2 O to Ethylene. to Ethylene
6.5 An Example of a Polar Reaction: Addition of H 2 O to Ethylene Addition of water to ethylene Typical polar process Acid catalyzed addition reaction (Electophilic addition reaction) Polar Reaction All
Additions to Metal-Alkene and -Alkyne Complexes
Additions to tal-alkene and -Alkyne Complexes ecal that alkenes, alkynes and other π-systems can be excellent ligands for transition metals. As a consequence of this binding, the nature of the π-system
and Ultraviolet Spectroscopy
Organic Chemistry, 7 th Edition L. G. Wade, Jr. Chapter 15 Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy 2010, Prentice all Conjugated Systems Conjugated double bonds are separated
Organocopper Reagents
rganocopper eagents General Information!!! why organocopper reagents? - Efficient method of C-C bond formation - Cu less electropositive than Li or Mg, so -Cu bond less polarized - consequences: 1. how
THE ORGANOMETALLIC CHEMISTRY OF THE TRANSITION METALS
THE ORGANOMETALLIC CHEMISTRY OF THE TRANSITION METALS Second Edition ROBERT H. CRABTREE Yale University New Haven, Connecticut A Wiley-Interscience Publication JOHN WILEY & SONS New York / Chichester /
CHEM 251 (4 credits): Description
CHEM 251 (4 credits): Intermediate Reactions of Nucleophiles and Electrophiles (Reactivity 2) Description: An understanding of chemical reactivity, initiated in Reactivity 1, is further developed based
Chemistry 335 Supplemental Slides: Interlude 2
Interlude 2: Shapes of Cyclic Molecules Recall from 2 nd year: - Rotation around C C single bonds is generally fast. - This leads to a variety of different conformers for any given molecule. - To evaluate
Oxidative Addition and Reductive Elimination
xidative Addition and Reductive Elimination red elim coord 2 ox add ins Peter.. Budzelaar xidative Addition Basic reaction: n + X Y n X Y The new -X and -Y bonds are formed using: the electron pair of
Catalytic Asymmetric Pauson-Khand Reaction. Won-jin Chung 02/25/2003
Catalytic Asymmetric Pauson-Khand eaction U. Khand; G.. Knox; P. L. Pauson; W. E. Watts J. Chem. Soc. Chem. Commun. 1971, 36 Won-jin Chung 02/25/2003 The General Pattern of the Pauson-Khand eaction Co
Elimination reactions
Chapter 9 Elimination reactions E2 and E1 reactions Competition between S N and E Elimination reactions Ch 9 #2 elimination and/or substitution 2 mechanisms ~ E2 and E1 E2: bimolecular elimination rxn
Oxidative Addition oxidative addition reductive elimination
Oxidative Addition We have seen how neutral ligands such as C 2 H 4 or CO can enter the coordination sphere of a metal by substitution. We now look at a general method for simultaneously introducing pairs
Nickel-Catalyzed Three-Component [3+2+2] Cocyclization of Ethyl Cyclopropylideneacetate and Alkynes
![Nickel-Catalyzed Three-Component [3+2+2] Cocyclization of Ethyl Cyclopropylideneacetate and Alkynes](/thumbs/77/74720708.jpg "Nickel-Catalyzed Three-Component [3+2+2] Cocyclization of Ethyl Cyclopropylideneacetate and Alkynes")
Nickel-Catalyzed Three-Component [3+2+2] Cocyclization of Ethyl Cyclopropylideneacetate and Alkynes Selective Synthesis of Multisubstituted Cycloheptadienes 1 2 Cat. Ni 0 1 2 Komagawa, S.; Saito, S. Angew.
Mechanisms of Inorganic Reactions HS -26
Mechanisms of Inorganic Reactions HS -26 A. Ligand Substitution Reactions Octahedral Co(III), Cr(III) Dissociative mechanism Square Planar Pt(II) Associative mechanism trans effect in Pt(II) complexes
Organic Chemistry. Unit 10
Organic Chemistry Unit 10 Halides Primary Carbons Secondary Carbons Tertiary Carbons IMPORTANCE?? REACTIONS!! Benzene C6H6 Aromatic functional group - C6H5 (IUPAC name - phenyl) Substitution Reactions
Basic Organic Chemistry Course code : CHEM (Pre-requisites : CHEM 11122)
Basic Organic Chemistry Course code : CHEM 12162 (Pre-requisites : CHEM 11122) Chapter 01 Mechanistic Aspects of S N2,S N1, E 2 & E 1 Reactions Dr. Dinesh R. Pandithavidana Office: B1 222/3 Phone: (+94)777-745-720
Copper-Catalyzed Synthesis of Esters from Ketones. Alkyl Group as a Leaving Group.
Copper-Catalyzed Synthesis of Esters from Ketones. Alkyl Group as a Leaving Group. akatani, Y.; Koizumi, Y.; Yamasaki, R.; Saito, S. rg. Lett. 2008, 10, 2067-2070. An Annulation Reaction for the Synthesis
The Final Learning Experience
Chemistry 210 Organic Chemistry I Fall Semester 2000 Dr. Rainer Glaser Examination #5 Reactions of Alcohols and Related Reactions The Final Learning Experience Wednesday, December 20, 2000, 1:00-3:00 Name:
Learning Guide for Chapter 17 - Dienes
Learning Guide for Chapter 17 - Dienes I. Isolated, conjugated, and cumulated dienes II. Reactions involving allylic cations or radicals III. Diels-Alder Reactions IV. Aromaticity I. Isolated, Conjugated,
Inorganic Chemistry Year 3
Inorganic Chemistry Year 3 Transition Metal Catalysis Eighteen Electron Rule 1.Get the number of the group that the metal is in (this will be the number of d electrons) 2.Add to this the charge 1.Negative
O H Hydrogen bonding promotes H-atom transfer from C H bonds for C-alkylation of alcohols
ydrogen bonding promotes -atom transfer from C bonds for C-alkylation of alcohols Jenna L. Jeffrey, Jack A. Terrett, David W. C. MacMillan Science 2015, 349, 1532-1536 Raffaele Colombo 9/26/2015 Raffaele
The Role of METAMORPhos Ligands in Transition Metal Complex Formation and Catalysis S. Oldenhof
The Role of METAMORPhos Ligands in Transition Metal Complex Formation and Catalysis S. Oldenhof Summary Catalysis plays a key role in the prosperity of our society, as catalysts are applied in the majority
Initials: 1. Chem 633: Advanced Organic Chemistry 2016 Final Exam
Initials: 1 ame: Chem 633: Advanced rganic Chemistry 2016 Final Exam This exam is closed note, closed book. Please answer the following questions clearly and concisely. In general, use pictures and less
Shi Asymmetric Epoxidation
Shi Asymmetric Epoxidation Chiral dioxirane strategy: R 3 + 1 xone, ph 10.5, K 2 C 3, H 2, C R 3 formed in situ catalyst (10-20 mol%) is prepared from D-fructose, and its enantiomer from L-sorbose oxone,
10 Chemical reactions in aqueous solutions
The Physics and Chemistry of Water 10 Chemical reactions in aqueous solutions Effects of water in reactions Hydration of reactants cause steric barriers Increases attraction between nonpolar reactants
11/5/ Conjugated Dienes. Conjugated Dienes. Conjugated Dienes. Heats of Hydrogenation
8.12 Sites of unsaturation Many compounds have numerous sites of unsaturation If sites are well separated in molecule they react independently If sites are close together they may interact with one another
Supplementary Information
3 Et 2 and TMSTf: A Synergistic Combination of Lewis Acids Eddie L. Myers a, Craig P. utts a and Varinder K. Aggarwal* a Contents Supplementary Information (a) Analysis of mixtures of TMSTf and 3 Et 2
Nucleophilic attack on ligand
Nucleophilic attack on ligand Nucleophile "substitutes" metal hapticity usually decreases xidation state mostly unchanged Competition: nucleophilic attack on metal usually leads to ligand substitution
CHEM Core Chemistry 3. Reaction Mechanisms in Organometallic Chemistry
E3012 - ore hemistry 3 eaction echanisms in Organometallic hemistry In an earlier section of this lecture course we considered the mechanisms of substitution reactions in organometallic species, and noted
Functionalization of terminal olefins via H migratory insertion /reductive elimination sequence Hydrogenation
M.C. White, Chem 153 verview -282- Week of ovember 11, 2002 Functionalization of terminal olefins via migratory insertion /reductive elimination sequence ydrogenation ML n E ydrosilylation Si 3 Si 3 ML
Preparation of alkenes
Lecture 11 אלקנים הכנה ותגובות של אלקנים: הידרוגנציה, סיפוח הידרוהלוגנים )כלל מארקובניקוב(, סיפוח הלוגנים והסטראוכימיה של תוצרי הסיפוח, הידרובורציה, אפוקסידציה, אוזונוליזה. 1 Preparation of alkenes 1.
Key ideas: In EAS, pi bond is Nu and undergoes addition.
Objective 7. Apply addition and elimination concepts to predict electrophilic aromatic substitution reactions (EAS) of benzene and monosubstituted benzenes. Skills: Draw structure ID structural features
Nitrogen Centered Radical Ligands Nagashima Nozomu
1 Nitrogen Centered Radical Ligands 2015. 7. 4. Nagashima Nozomu 1. Introduction 2 3 Aminyl radical 1) D. E. Wiliams, JACS, 1966, 88, 5665 2) Y. Teki et al. JOC, 2000, 65, 7889 Sterically protected aminyl
Rearrangement: a single reactant rearranges its
Chapter 5: An overview of organic reactions 5.1 Kinds of organic reactions Even though there are hundreds of reactions to study, organic chemistry is governed by only a few key ideas that determine chemical
Asymmetric Catalysis by Lewis Acids and Amines
Asymmetric Catalysis by Lewis Acids and Amines Asymmetric Lewis acid catalysis - Chiral (bisooxazoline) copper (II) complexes - Monodentate Lewis acids: the formyl -bond Amine catalysed reactions Asymmetric
Ethers. Chapter 14: Ethers, Epoxides, & Sulfides. General Formula: Types: a) Symmetrical: Examples: b) Unsymmetrical: Examples: Physical Properties:
Chamras Chemistry 106 Lecture Notes Examination 1 Materials Chapter 14: Ethers, Epoxides, & Sulfides Ethers General Formula: Types: a) Symmetrical: Examples: b) Unsymmetrical: Examples: Physical Properties:
Name: Chapter 3: The Nature Of Organic Reactions: Alkenes
Name: Chapter 3: The Nature Of Organic Reactions: Alkenes 1 Vocabulary cis-trans isomerism: E,Z designation: Addition: Elimination: Substitution: Rearrangement: Homolytic: Heterolytic Homogenic: Heterogenic: