UCF - ORGANIC CHEMISTRY 1 - PROF. DAOUDI UCF PROF. DAOUDI EXAM 3 REVIEW.

Transcription

1 UCF PROF. DAOUDI EXAM 3 REVIEW 1

2 PRACTICE: Identify the most stable and the least stable alkene PRACTICE: Create the full arrow pushing mechanism which shows all intermediates and all products that result from these reactions. If alkenes are produced, indicate which is major and minor. 2

3 PRACTICE: Draw the product(s) from the following reaction. a) Clearly label each drawing with the correct stereochemistry-(use R & S for chiral centers, if any). b) Clearly label pairs of enantiomers & diastereomers, if any. 3

4 PRACTICE: Fill in the missing reagents 4

5 PRACTICE: Which of the following is ( Z )-3,5-dimethyl-3-nonene? 5

6 PRACTICE: Name the following compound correctly using accurate R or S and E and Z nomenclature. PRACTICE: Draw the product(s) from the following reaction. Show any relevant regio- and or stereochemistry and asterisk any chiral centers. 6

7 PRACTICE: Which carbocation would not be likely to undergo rearrangement? PRACTICE: Provide the reagents necessary to achieve the following transformation. 7

8 PRACTICE: Rank in order of leaving group ability (1 = best leaving group, 4 = worst leaving group). PRACTICE: Which is the order from fastest to slowest for the rates of the SN2 reactions of these alkyl bromides with CH 3 S / DMSO? 8

9 PRACTICE: Which compound would react fastest by an S N 2 mechanism? PRACTICE: Identify the correct potential energy diagram for a tertiary alkyl chloride (3 RCl) versus primary alkyl chloride (1 RX) undergoing an S N 2 reaction. Provide rationale to support your choices. 9

10 PRACTICE: In the S N 2 reaction, the "2" stands for a) two reactants in the reaction b) two steps in the reaction c) two intermediates in the reaction d) bimolecular kinetics for the reaction PRACTICE: Provide a complete mechanism for the following transformation. 10

11 PRACTICE: Use A-G to label the graph with the structures given for the reaction: 11

12 PRACTICE: Predict the products of the following synthesis: 12

13 PRACTICE: Create the full arrow pushing mechanism which shows all intermediates and all products that result from these reactions. If alkenes are produced, indicate which is major and minor. PRACTICE: Which solvent would favor and S N 2 style mechanism? A) Methanol B) Dimethyl formamide C) Water D) Acetic acid 13

14 PRACTICE: Rank the species below in order of increasing nucleophilicity in hydroxylic solvents (weakest nucleophile first): CH 3 CO 2 -, CH 3 S -, HO -, H 2 O. a) H 2 O < CH 3 S- < CH 3 CO 2 - < HO - b) H 2 O < HO - < CH 3 CO 2 - < CH 3 S - c) H 2 O < CH 3 CO 2 - < HO - < CH 3 S - d) CH 3 CO 2 - < H 2 O < HO - < CH 3 S - 14

15 PRACTICE: Circle non-polar, polar aprotic, or polar protic to describe each of the following solvents: 15

16 PRACTICE: Create the full arrow pushing mechanism which shows all intermediates and all products that result from these reactions and label minor and major products if they are not equal in potential energy. 16

17 PRACTICE: Which of the following undergoes S N 1 solvolysis in ethanol/water at the fastest rate? a) A b) B c) C d) D PRACTICE: What is the nucleophile in the following reaction? 2 H 2 O + H 3 C-X H 3 C-OH + H 3 O + + X - a. H 2 O b. H 3 C c. X - d. H 3 C-OH e. H 3 O + f. CH 3 -X 17

18 PRACTICE: Propose a successful synthesis of 1-decene from 1-bromodecane. Be sure to include specific reagents and solvents. 18

19 PRACTICE: Predict the major elimination product for the following reaction: PRACTICE: In the dehydration of 2-bromo-2-methylbutane with potassium hydroxide, which hydrogen atom is preferentially abstracted? 19

20 PRACTICE: A. Predict the product of the following reaction. B. Construct a reaction mechanism that accounts for the product proposed. C. Construct a reaction coordinate diagram for the reaction. Label all axes. Note that the reaction has three steps: The 1st is fast and endothermic. The 2nd is slow and endothermic. The 3rd is fast and exothermic. The overall reaction is exothermic. D. Using complete sentences state how you have shown that the 1st and 3rd steps are fast and that the 2nd reaction is slow. 20

21 PRACTICE: Propose a mechanism for the following reaction PRACTICE: Predict the major product 21

22 PRACTICE: Which of the following is the double substitution product of the reaction below? 22

23 PRACTICE: The reaction shown below would be expected to produce as major products which of the following compounds? 23

24 PRACTICE: Determine the mechanism and predict the product of the reaction: 24

25 PRACTICE: Determine the anticipated product(s) for the reaction below. Using correct mechanistic arrows, provide the step-by-step mechanism that shows how the following substitution reaction proceeds. You do not need to show stereochemistry while providing the mechanism, but show correct stereochemistry in the final product(s). (Circle the major product if multiple products are formed.) 25

26 PRACTICE: Predict the product: PRACTICE: Give all possible product/products and designate stereoselectivity &/or regioselectivity by using wedges and dashes. 26

27 PRACTICE: Determine the mechanism and predict the product of the reaction: 27

28 PRACTICE: Provide the structural formula for the reactant in the following reaction. 28

29 PRACTICE: The reaction of Br 2 to cyclohexene would produce the compound(s) represented by structure(s): Circle all that apply 29

30 PRACTICE: Predict the products of the following synthesis: 30

31 PRACTICE: Give all possible product/products and designate stereoselectivity &/or regioselectivity by using wedges and dashes. PRACTICE: Determine the mechanism and predict the product of the reaction: 31

32 PRACTICE: Supply a structural formula for the major organic product ; if no reaction occurs, write N.R. Give the best possible answer. Be sure to show stereoisomers properly when necessary. PRACTICE: Draw the structural formula of the major organic product(s) in the box for the following reaction. 32

33 PRACTICE: Which one of these structures best explains the reason why epoxide 1 gives compound 2 instead of compound 3 upon reaction with HBr. PRACTICE: Predict the product of the following reaction showing stereochemistry if applicable. 33

34 PRACTICE: Predict the major product PRACTICE: Predict the product of the following reaction. Show stereochemistry when applicable. 34

35 PRACTICE: Complete the following set of reactions by supplying the missing reagents 35

36 PRACTICE: For each of the following, supply a structural formula for the major organic product(s) when the product(s) is(are) not given: if no reaction occurs, write N.R. Provide the following when a product is given. If an organic reactant is missing, supply a structural formula; if an organic reactant (reagent) or catalyst is missing, simply give a formula. Give the best possible answers. Be sure to show stereoisomers properly when necessary. PRACTICE: Fill in the missing reagents 36

37 PRACTICE: Predict the product for the reaction below. 37

38 PRACTICE: What is the expected major product of the following reaction sequence? 38

39 PRACTICE: Fill in the missing reagents: 39

40 PRACTICE: Predict the product of the reaction: 40

41 PRACTICE: Predict the product of the reaction: 41

42 PRACTICE: Predict the product of the reaction: PRACTICE: Starting with 1-hexene, which synthetic sequence below gives 2-cyanohexane? a) (1) H 2 SO 4 (cat.), H 2 O (2) NaCN b) (1) HBr/peroxide (2) NaCN c) (1) HBr (2) NaCN d) (1) Br 2, H 2 O (2) NaCN 42

43 PRACTICE: Provide an efficient multistep synthesis for the following conversion of the given starting compound into the target compound. For this problem, do not give a mechanism with curved arrows. For the synthesis, more than one functional group transformation is required. For each functional group transformation, give all necessary reagents and catalysts and give a structural formula of the organic product. Also give hv and/or heat when necessary. Show stereochemistry appropriately when necessary. 43

44 PRACTICE: Which of the given reaction schemes would produce the molecule shown below? 44

45 PRACTICE: Predict the reagent(s) required to complete the following transformation: 45

46 PRACTICE: Fill in the missing reagents: 46

47 PRACTICE: Predict the major product of the reaction shown. 47

48 PRACTICE: Compound A reacts with HBr via an S N 1 process leading to 3 different constitutional isomers. Draw the structure of these products. 48