Recent Developments in Baylis-Hillman Reaction
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1 ecent Developments in Baylis-illman eaction ---chanism Exploration and Application of ew Catalysts Guixing Wang Michigan State University ct. 26, 2005
2 Seminar utline Introduction ecent riginchanism Exploration chanism Application of ew Catalysts Catalysts Conclusion Scope and Limitations Acknowledgement
3 Carbinol Addition PCy 3 C 2 C C C 2 Conversion <23% 120 o C, 2h C() : C, C 2 C 3 ; : C 3, C 2 C 3, (C 2 )C 3, C(C 3 ) 2, C 6 5, p-cl-c 6 4, p-c 3 -C 6 4 Proposed mechanisms: PCy 3 Cy 3 P Cy 3 P Cy 3 P 2 C C PCy 3 C PCy 3 Cy 3 P Cy Cy PCy 3 2 C C P C Cy Morita, K.; Suzuki, Z.; irose,. Bull. Chem. Soc. Jpn. 1968, 41, 2815
4 German Patent: Baylis-illman(B) eaction Three-component reaction: ' EWG ucleophilic trigger tert. Amine ' EWG Electrophile Activated alkene = yl, Alkyl, eteroaryl; '=, C, Alkyl =, C, Ts, S 2 Ph EWG= Electron-withdrawing group; C, C, C, C, P(Et) 2, S 2 Ph, S 3 Ph, SPh EWG Vinyl anion Baylis, A. B.; illman, M. E. D. Chem. Abstr. 1972, 77, Drewes, S.; Freese, S. D.; Emslie,. D.; oss, G..P. Synth. Commun. 1988, 18, 1565 Aggarwal, V. K.; Emme, I.; Fulford, S. Y. J. rg. Chem. 2003, 68,
5 Generally Accepted chanism + Ph DABC Ph C ate-determining and stereocontrolling step Ph A Ph B Ph Ph + C ill, J. S.; Isaacs,. S. Tetrahedron Lett. 1986, 27, 5007 Fort. Y.; Berthe, M. C.; Caubere, P. Tetrahedron 1992, 48, 6371
6 riginal Catalysts DABC Quinuclidine Indolizine pka ydroxyquinuclidine Ph A B (-) (-) Drewes, S. E.; Freese, S. D.; Emsile,.D.; oos, G.. P. Synth. Commun. 1988, 18, 1565 Aggarwal, V. K.; Emme, I.; Fulford, S. Y. J.rg.Chem. 2003, 68, 692
7 Scope and Limitations Scope: Limitations Low rate : days or weeks Low conversion Low optical purity igh pressure Basavaiah, D; ao, A. J.; Satyanarayana, T. Chem. ev. 2003, 103, 811
8 Ways to vercome the Limitations Enhance the rates of rate-determining step (DS) Design more efficient catalysts Enhance the rates Improve yields and enantioselectivity eevaluating the mechanism Explain phenomena ate-determining step Stereocontrolling step
9 Seminar utline Introduction ecent chanism Exploration Generally accepted mechanism Application of ew Catalysts Two new mechanisms Conclusion Acknowledgement
10 Catalytic Cycle for B eaction K Zwitterion intermediate 1 7 Step 1 Step 2 DS Intramolecular proton transfer k 2 1 C 4 Direct proof of mechanism: Trap all the intermediates Characterize them Step Santos, L. S.; Pavam, C..; Almeida, W. P.; Coelho. F; Eberlin, M.. Abgew. Chem. Int. Ed. 2004, 43, 4330
11 Trapped Intermediate C 2 CCCl C 2 Cl K Step 1 Step 2 DS k 2 Intramolecular proton transfer 3 Zwitterion Intermediate 1 C Step B Cl 1) Elimination 2) C 2 Cl 2 81% A Drewes.. L.; jamela,. D.; Emslie,..; Field, J. S. Synth. Commun. 1993, 23, 2807
12 Electrospray Ionization and Tandem Mass Spectrometry ESI: Transfer protonated intermediates into the gas phase MS-1: Select different intermediates for collision-induced dissociation MS-2: Characterize the intermediates Wilson, S. ; Perez, J,; Pasternak, A. J. Am. Chem. Soc. 1993, 115, 1994 Smith,. D.; Loo, J. A.; Edmonds, C. G.; Barinaga, C. J.; Udseth,.. Anal. Chem. 1990, 62, 882
13 Selected eactions S 4a C + 2a C 3 DABC,.T. 1a S 7a C 2 C 3 2 C + DABC 1b C 2 C 3 4b 2b C 3,.T. 2 7b eutral zwitterionic intermediates are in equilibrium with their protonated forms in methanolic solution. Santos, L. S.; Pavam, C..; Almeida, W. P.; Coelho, F.: Eberlin, M.. Angew. Chem. Int. Ed. 2004, 43, 4330
14 [1a+] + 1a m/z 113 C 3 2a ESI(+)-MS S 4a C + 1 C 3 1a 2a 4a, 1 = thiazolyl 2a [3a+] + m/z 199 C 3 C 3 DABC 1a,.T. C 3 1 me S C 3 1 C 2 C 3 C 3 7a S [6a+] + m/z 312 C 3 1a Santos, L. S.; Pavam, C..; Almeida, W. P.; Coelho, F.; Eberlin, M.. Angew. Chem. Int. Ed. 2004, 43, 4330
15 ESI(+)-MS 1a 2 C + 4b 2a 1 4b, 1 = 4-2 Ph 2b C 3 DABC 1b, C.T b 1 6b C 3 7b C 2 C 3 C 3 C 3 [6b+] + m/z Santos, L. S.; Pavam, C..; Almeida, W. P.; Coelho, F.; Eberlin, M.. Angew. Chem. Int. Ed. 2004, 43, 4330
16 Tandem Mass Santos, L. S.; Pavam, C..; Almeida, W. P.; Coelho, F.; Eberlin, M.. Angew. Chem. Int. Ed. 2004, 43, 4330
17 Tandem Mass Santos, L. S.; Pavam, C..; Almeida, W. P.; Coelho, F.; Eberlin, M.. Angew. Chem. Int. Ed. 2004, 43, 4330
18 [1a+] + m/z 113 C 3 DABC 1a 2a thyl acrylate (Activated alkene) 1 [3a+] + m/z 119 C 3 C 3 4a, 1 = Thiazolyl 4b, 1 = 4-2 Ph Intercepted and characterized the expected intermediates DABC (1a) 1 5a, 5b C 3 C 3 1 6a, 6b 1 C 2 C 3 7a, 7b Baylis-illman adduct Santos, L. S.; Pavam, C..; Almeida, W. P.; Coelho, F.; Eberlin, M.. Angew. Chem. Int. Ed. 2004, 43, C 3 S [6a+] + m/z 312 C 3 [6b+] + m/z 350 C 3 C 3 2
19 Seminar utline Introduction ecent chanism Exploration Generally accepted mechanism Trap one intermediate Characterize intermediates by ESI and tandem mass Two new mechanisms Change of DS Consumption of two equivalents of aldehyde
20 ne Phenomenon ----ates Accelerated in Protic Solvents C + PhC DABC Ph C Solvent Water, Formamide thanol -methylacetamide Time (h) Yield = 90-98% TF 3-5 d + Carbonyl compound 3-QD Water Carbonyl compound Benzaldehyde o-anisaldehyde Isobutyraldehyde Time (h) Yield (%) Formalin 4 99 Ague, J.; lubin,.; Lubineau, A. Tetrahedron Lett. 1994, 43, 7949 Aggarwal, V. K.; Dean, D. K,; reu, A.; Williams,. J. rg. Chem. 2002, 67, 510
21 ow to Explain with the chanism 2 Autocatalysis? Step A 1 7 Step Intramolecular proton transfer Step 3 Step 2 1 C DS B DS is Step 3 Ameer, F.; Drewes, S. E.; Freese, S.; Kaye, P. T. Synth. Commun. 1988, 18, 495 Yamada, Y. M. A.; Ikegami, S. Tetrahedron Lett. 2000, 41, 2165 Aggarwal, V. K.; Emme, I.; Fulford, S. Y. J. rg. Chem. 2003, 68, 692 Aggarwal, V. K.; Fulford, S. Y.; Lloyd-Jones, G. C. Angew. Chem. Int. Ed. 2005, 44, 1706
22 Autocatalysis Catalyst (5%mol) + eat Autocatalysis: the product of the reaction is enhancing the rate. eaction rate is slow at first, and becomes faster. --- Quinuclidine ydroxyquinuclidine Aggarwal, V. K.; Emme, I.; Fulford, S. Y. J. rg. Chem. 2003, 68, 692
23 Quinuclidine-Based Catalysts on ates of B eaction --- Quinuclidine ydroxyquinuclidine --- DABC Acetoxyquinuclidine Cloroquinuclidine Quinuclidinone Aggarwal, V. K.; Emme, I.; Fulford, S. Y. J. rg. Chem. 2003, 68, 692
24 Protic Additives on ates of B eaction QD (3 mol%) + Additives equiv of triethanolamine equiv of methanol equiv of methanol equiv of formamide equiv of methanol equiv of water --- o additives Further rate enhancements were observed Proton transfer step is the DS Aggarwal, V. K.; Emme, I.; Fulford, S. Y. J. rg. Chem. 2003, 68, 692
25 ow to Decide the DS (D) Ph 1: = Et 6 (D) 1) 3 2 3) B (D) 3 Ph 2) (D) A PhC 4 A mixutre of d-acrylate (d-1) and acrylate (1) with 1:1 ratio A B A If primary step 3 is kinetic DS, a isotope primary effect KIE (KIE): to increase a bond the mole to the fraction isotopically of d-1substituted in the acrylate. (x d-1 ). atom is broken in DS. K /K D 2 If step 2 is DS, an inverse KIE to decrease An the inverse mole fraction KIE: coordination of d-1 the of acrylate.(x the d-1 ). reaction center increases in the transition state. K /K D <1. Aggarwal, V. K.; Fulford, S. Y.; Lloyd-Jones, G. C. Angew. Chem. Int. Ed. 2005, 44, 1706
26 Kinetic Study and Simulation (D) Et + Ph Quinuclidine Ph (D) Et In the early phase, step 3 is DS atio stabilizes in the later phase elationship between conversion and the mole fraction d-1 (x d-1 =[d-1]/[1+d-1]) Aggarwal, V.K.; Fulford, S.Y.; Lloyd-Jones, G.C. Angew. Chem. Int. Ed. 2005, 44, 1706
27 Kinetic Study and Simulation B K /K D =4.8 for step 3 (non-autocatalyzed) K /K D =1 for step 3 (autocatalyzed) A change in DS from step 3 to step 2 Lines: simulation through data points Circles: observed data Aggarwal, V. K.; Fulford, S. Y.; Lloyd-Jones, G. C. Angew. Chem. Int. Ed. 2005, 44, 1706
28 A Change in DS Disfavored Intramolecular four-membered direct proton transfer DS is step 3 (non-autocatalyzed) DS is step 2 (autocatalyzed) As the change in the [product] Aggarwal, V. K.; Fulford, S. Y.; Lloyd-Jones, G. C. Angew. Chem. Int. Ed. 2005, 44, 1706
29 Insights of Enantioselectivity Low success rate in design of chiral catalysts: 1 C 4 Chiral Catalyst 3 Step 2 Chiral Catalyst DS and stereocontrolling step * 1 5 Likely origin of enantioselection in the Baylis-illman reaction C + u DS fast * * slow slow slow * u * Aggarwal, V. K.; Fulford, S. Y.; Lloyd-Jones, G. C. Angew. Chem. Int. Ed. 2005, 44, 1706
30 Seminar utline Introduction ecent chanism Exploration Generally accepted mechanism Two new mechanisms Change of DS DS is the proton transfer step 3 Explain the effect of protic additives Insights of enantioselection Consumption of two equivalents of aldehyde
31 ne Phenomenon ----Dioxanone Formation C 2 C 2 DABC (cat.) + C + C 4 2 C DABC ' C ' Time (h) Temp. atio (5:6) + Yield (%) Ph Ph 2, 6-DMP i-pr ' rt rt rt 0:1 0:1 4:1 ' , 6-DMP 6 0 6:1 36 2,4,6-DMP 14 rt 7:1 43 Perlmutter, P.; Puniani, E.; Westman, G. Angew. Tetrahedron Lett, 1996, 37, 1715
32 Dioxanone in Asymmetric B eaction Leachy s enantioselective B reaction: + S + Yield: 22-98% ee>99% atakeyama s dioxanone kinetic resolution: CF 3 + CF 3 Modified quinidine + Yield: 31-57% ee: 91-99% Yield: 11-57% ee: 4-7% Brzezinski, L. J.; afel, S.; Leahy, J. W. J. Am. Chem. Soc. 1997, 119, 4317 Iwabuchi, Y.; akatani, M.; yokoyama,.; atakeyama, S. J. Am. Chem. Soc. 1999, 121, 10219
33 rder Plots + DABC DMS ate = k obs [Aldehyde] 2 [thylacrylate][dabc] Price, K. E.; Broadwater, S. J.; Jung,. M.; McQuade, D. T. rg. Lett. 2005, Price, K. E.; Broadwater, S. J.; Walker, B. J.; McQuade, D. T. J. rg. Chem, 2005, 70, 3980
34 ew Intermediate ate = k obs [Aldehyde] 2 [DABC][thylAcrylate] equiv methyl acrylate 2 3 K 1 3 Step 1 Step 2 DS k 2 1 C 4 Step 2 is not the DS 2 equiv aldehyde Inverse KIE has been oberserved 7 1 equiv DABC 3 Intramolecular proton trasnfer Step 3 1 5C- bond is broken Pimary KIE has been observed Price, K. E.; Broadwater, S. J.; Jung,.M.; McQuade, D. T. rg. Lett. 2005, Santos, L. S.; Pavam, C..; Almeida, W. P.; Coelho. F; Eberlin, M.. Abgew. Chem. Int. Ed. 2004, 43, 4330
35 A ew chanism 1 (D) 2 3 (D) Price, K. E.; Broadwater, S. J.; Walker, B. J.; McQuade, D. T. J. rg. Chem, 2005, 70, 3980
36 A ew chanism Dioxanone 8 ormal B adduct Price, K. E.; Broadwater, S. J.; Walker, B. J.; McQuade, D. T. J. rg. Chem, 2005, 70, 3980
37 ate Law 1 (D) (D) 2 4 K 1 K K 3 k Steady-state approximation Equilibrium approximation ate = k 2 k 3 k 4 [4] 2 k k + k k k [1][2][4] k3k4[4] + k 1k 2k 3 + k 1 k 2 k 4 k k k k [1][2][4] (1) ate = = (2) K1K2K3k4[1][2][4] k 1k 2k 3 Price, K. E.; Broadwater, S. J.; Walker, B. J.; McQuade, D. T. J. rg. Chem, 2005, 70, 3980
38 esolve Four Unexplained Features Sluggish reaction rates Dioxanone formation Difficult stereocontrol Acceleration with protic additives
39 Sluggish eaction ates k k k k [1][2][4] ate = = K1K2K3k4[1][2][4] k 1k 2k 3 k k k k [1][2][4] ate = = 2 k k k [4] + k k k [4] + k k k + k k k K obs [1][2][4] K obs has an inverse dependence on [Aldehyde] For aldehydes whose k 2, k 3 k 4 the overall reaction is attenuated relative to aldehydes whose k 2, k 3 k 4 As the reaction consumes aldehyde, k 2 and k 3 decrease, the equilibrium approximation becomes invalid, and the reaction slows dramatically as a function of aldehyde consumption. Price, K. E.; Broadwater, S. J.; Walker, B. J.; Mcquade, D. T. J. rg. Chem, 2005, 70, 3980
40 Dioxanone Formation + 8 Intermediate 8 could cyclize to yield dioxanone Price, K. E.; Broadwater, S. J.; Walker, B. J.; Mcquade, D. T. J. rg. Chem, 2005, 70, 3980
41 Difficult Stereocontrol The elimination proceeds through a diastereometric, hemiacetal transition state Aux * ' Lewis Base * The chiral auxiliary approach Price, K. E.; Broadwater, S. J.; Walker, B. J.; McQuade, D. T. J. rg. Chem, 2005, 70, 3980 The optically active Lewis base approach
42 Acceleration with Protic Additives ate increase is a medium effect in which the ionic transition states are stabilized in the presence of polar solvents. Price, K. E.; Broadwater, S. J.; Walker, B. J.; McQuade, D. T. J. rg. Chem, 2005, 70, 3980
43 Seminar utline Introduction ecent chanism Exploration Generally accepted mechanism Two new mechanisms Change of DS Consumption of two equivalents of aldehyde emiacetal intermediate formation Explanation of four features
44 Seminar utline Introduction ecent chanism Exploration Application of ew Catalysts Proazaphosphatrane sulfide Bifunctional catalysts
45 Bicyclic Proazaphosphatrane P 1a = 1b = ibu 1c = ipr Activated alkene C 1) P(C 2 C 2 )3/TF, -84 o C 2) C, 3h, -84 o C 3), 5min, -84 o C 88% E:Z=78 : 22 C C C C C 1a + PhC Ph C Ph C Ph C Ph C Lensink, C.; i, S. K.; Daniels, M.; Verkade, J. G. J. Am. Chem. Soc. 1989, 111, 3478 Kisanga, P. B.; Verkade, J. G. J. rg. Chem, 2002, 67, 426 You, J.; u, J.; Verkade, J. G. Angew. Chem. Int. Ed. 2003, 42, 5054
46 Proazaphosphatrane Sulfide S P C Cyclohex-2-en-1-one (3 eq.) 2a = 2b = ibu 2c = ipr 2 20mol% 2a, C 2 Cl 2,.T. 2 TiCl (1 eq.) 95%, 5%, 4 5 days min You, J.; u, J.; Verkade, J.G. Angew. Chem. Int. Ed. 2003, 42, 5054
47 ow the Catalyst Works S P P S P S P S P 2a = 95%, 5min 2b = ibu 2c = ipr C Cyclohex-2-en-1-one (3 Eq.) 2 Cat., C 2 Cl 2, r.t. TiCl (0.05 eq.) 4 (0.05 eq.) 5 (0.05 eq.) 6 (0.05 eq.) 48%, 10 min 69%, 10 min 55%, 10 min 59%, 10 min You, J.; u, J.; Verkade, J.G. Angew. Chem. Int. Ed. 2003, 42, 5054
48 chanistic Investigation Cl 4 Ti C Step 2 4 Intramolecular proton transfer 3 Step S P You, J.; u, J.; Verkade, J.G. Angew. Chem. Int. Ed. 2003, 42, 5054
49 S P 2a 2a / TiCl 4 Aldehyde + Enone Product Aldehyde Enone Product Time (min) Yield (%) 2 C C C 3 C C 3 2 C C C C 3 You, J.; u, J.; Verkade, J. G. Angew. Chem. Int. Ed. 2003, 42, 5054
50 Seminar utline Introduction ecent chanism Exploration Application of ew Catalysts Proazaphosphatrane sulfide ax P Substantially increased reaction rate Bifunctional catalysts
51 Concept of Multifunctional Catalysis A synergistic activation--- specific control of transition state structure, high enantioselectivity Somei..; Asano, Y.; Yoshida, T.; Takizawa, S.; Yamataka,.; Sasai,. Tetrahedron Lett. 2004, 45, 1841 amashima, Y.; Sawada, D.; Kanai, M.; Shibasaki, M. J. Am. Chem. Soc. 1999, 121, 2641
52 Lewis Base Lewis Acid (LBLA) Catalysts P Phosphine Lewis base PPh 2 LB1 Shi, M.; Chen, L. Chem. Comm. 2003, 1310 Shi, M.; Chen, L.; Li, C. J. Am. Chem. Soc. 2005, 127, 3790 Chiral phosphine LBLA
53 Analysis of LB1 Ts PPh 2 LB1 Cl 1e Ts LB (10mol%) + TF, 0 o C Cl The importance of hydroxyl group 2e Yield: 72% ee: 94% Et PPh 2 S PPh 2 PPh 2 PPh 2 PPh 2 LB2 Yield: 13% ee: 20%, LB3 Yield: 17% ee: 22%, LB4 o eaction LB5 Yield: 35% ee: 39%, Uozumi, Y.; Tanahashi, A.; Lee, S.-Y.; ayashi, T. J. rg. Chem. 1993, 58, 1945 Shi, M.; Chen, L.; Li, C. J. Am. Chem. Soc. 2005, 127, 3790
54 BA Lewis acid + Key enolate intermediate PPh 2 P Ph 2 Lewis base LB C=Ts Ts C C=Ts Ts Ph Ph P Ts Ts D PPh 2 Ts E PPh 2 Ph P Ph Ts Favored Disfavored S Shi, M.; Chen, L.; Li, C. J. Am. Chem. Soc. 2005, 127, 3790
55 Aza-B eaction with LB1 Catalyst PPh 2 LB1 (10mol%) Ts 1 + TF, -30 o C, or MS 4A 2 o. Time (h) Yield (%) ee (%) 1a C 6 5 Ts b p-c 6 4 Ts c p-clc 6 4 Ts d m-clc 6 4 Ts e p- 2 C 6 4 Ts f m- 2 C 6 4 Ts g p-clc 6 4 Ms h p-clc 6 4 p-clc 6 4 S Shi, M.; Chen, L.; Li, C. J. Am. Chem. Soc. 2005, 127, 3790
56 Position of LBLA spacer LB Lewis base unit Bronsted acid units BIL unit Shi, M.; Chen, L.; Li, C. J. Am. Chem. Soc. 2005, 127, 3790 Matsui, K.; Takizawa, S.; Sasai,. J. Am. Chem. Soc. 2005, 127, 3680
57 Proposed chanism spacer LB Lewis base unit Bronsted acid units BIL unit α,β unsaturated carbonyl compound Imine Allyl amine Michael reaction Bifunctional organocatalyst etro-michael reaction (β elimination) 3 3 LB 1 LB LB: Lewis base Aldol reaction Matsui, K.; Takizawa, S.; Sasai,. J. Am. Chem. Soc. 2005, 127, 3680
58 Position of Lewis base + Ts Ph Catalyst 10mol% Ts Ph Matsui, K.; Takizawa, S.; Sasai,. J. Am. Chem. Soc. 2005, 127, a: (S)-3-[4-(dimethylamino)pyridin-2-yl]BIL 1b: (S)-3-[4-(dimethylamino)pyridin-3-yl]BIL 2a: (S)-3-(-methyl--3-pyridinylaminomethyl)BIL Yield: 41%, ee: 73% 2b: (S)-3-(-methyl--2-pyridinylaminomethyl)BIL 2c: (S)-3-(-methyl--4-pyridinylaminomethyl)BIL
59 ow the Catalyst Works ne pair of acid-base unit fixes the conformation The other pair activates electrophile and nucleophile 3 6a ( = ipr) Yield: 93%, ee: 87% ' 6a ( = ipr) 7a: 1 =, 2 = Yield: 5%, ee: 24% 7b: 1 =, 2 = Yield: 85%, ee: 79% 8 9a: = C 2 9b: = (C 2 ) 2 9c: =C 2 Matsui, K.; Takizawa, S.; Sasai,. J. Am. Chem. Soc. 2005, 127, 3680
60 Aza-B eaction with Bifunctional Catalyst Entry 1 3 Ts + 2 6a (= ipr) Ts 10mol% Toluene: CPME (1:9), -15 o C 5 3: 1 4: 2 Time (h) Yield (%) ee (%) 1 Ph p-cl-c m-cl-c p-br-c p--c furyl 48 quant naphthyl p- 2 -C Et p- 2 -C p- 2 -C Matsui, K.; Takizawa, S.; Sasai,. J. Am. Chem. Soc. 2005, 127, 3680
61 Seminar utline Introduction ecent chanism Exploration Application of ew Catalysts Proazaphosphatrane sulfide Bifunctional catalysts ne Pair of LBLA Two Pairs of LBLA
62 Conclusion Different mechanisms focus on different aspect of the reaction chanisms offer us a way to think of the reaction, design of the catalysts Co-operative activation of both reactants in intermolecular reactions by a bifunctional catalyst gives a better control of the stereochemistry
63 Acknowledgement Dr. Wagner Dr. Tepe Dr. Friebe Tepe s Group Adam, Brandon, Chris, James, Jason, Manasi, Sam 1, Sam 2, Vasudha ua, icki, Patrick
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