HO HO. 1) BH 3 HCl. + enantiomer either one may be drawn 4. + enantiomer either one may be drawn 4 1) O 3

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1 . (0 points) Page 1 A. Reaction analysis: provide the requested information in each of the following chemical transformations. how all missing starting materials and products unless otherwise indicated, and if any reaction results in a stereoisomeric mixture, draw one and indicate "+ enantiomer," "+ diastereomer," or "+ more than one stereoisomer" in the box (ii) The product shown forms with (circle the best answer): KMn no other stereoisomers its enantiomer its diastereomer with > other stereoisomers (ii) Major regioisomer only + enantiomer either one may be drawn 1) B ) /a + enantiomer either one may be drawn (ii) Draw the organic products with the info given: equiv 1 -MR: 1 peak 1 equiv 1 -MR: peaks 1 equiv 1 -MR: 1 peak a 1) ) ( ) 6 (d) right does not have to be D (ii) R R Pt draw one and "+ enantiomer" draw one and "+ enantiomer

2 . (6 points) Page n the following reactions, an optically pure starting material is transformed using slightly different reagents and/or conditions. Predict the product(s) for each transformation, using the information given. Then consider how the changes might affect the rate of that same reaction path. an optically inactive mixture containing two chiral compounds: 7 1 ; draw each a 1 (R) () assuming that the same reaction mechanism occurs (with identical or analogous product(s) forming)... (ii) if 1 was changed to (iii) if 1 was changed to Br (iv) if was doubled in concentration (v) if a was changed to a single chiral product: 7 11 a (ii) if was changed to (iii) if a was doubled in concentration

3 . (0 points) Page A. DB is a strong, bulky base that is often used to encourage elimination reactions over substitution reactions. n both of the following cases, the resulting bimolecular elimination reaction yields a single major product which can be explained by conformational favorability in the starting material. Draw the product for each and draw the conformation that favors its formation. Using a chair, draw the conformation (ii) elected product that is favored and leads to the product DB 1 equivalent Draw the conformation appropriately: draw both axial and equatorial positions for each ring atom that has a substituent. 5 Using a ewman projection, draw the conformation that is favored and leads to the product (ii) elected product DB View the - bond as indicated 5 B. omplete the following regioselective reactions by drawing the intermediate of highest energy that forms during the reaction (best resonance contributor if applicable), and draw the final product(s) as well. f either the intermediate or the regioselected product(s) forms as a stereoisomeric mixture, draw one and write "+enantiomer" or "+diastereomer" in the box. highest energy intermediate (ii) Final product(s) predicted to form no stereochem no partial -1 if "+ enantiomer" -1 if "+ enantiomer" highest energy intermediate predicted to form (ii) Final product(s) (cat.) no partial -1 if "+ enantiomer" + diastereomer

4 A. V. (8 points) Page onsider the reaction scheme below, and provide the missing information. ote that stereochemistry is not considered here MR: 6 signals heat dehydration Major product (cat.) 9 18 Electrophilic addition with rearrangement t has been proposed that the addition product forms as a result of several mechanistic steps, including two carbocation shifts. Draw this (the most straightforward) curved arrow mechanism for this transformation. You should choose the appropriate acid/conjugate base pair for any proton transfers, and be sure to regenerate your acid. 1 points/intermediate points/mechanism (per step) Grading stops when a chemically illogical step is shown The final product shown will form as a single unique compound a racemic mixture a diastereomeric mixture a mixture of or more stereoisomers 5 B. The same starting material can be transformed to give a structural isomer of the compound formed above with no evidence of rearrangement. Draw only the connectivity of the organic product ( 9 18 ) that forms, and answer the question about how it forms. 1) B ) /a ) a ) 9 18 The final product here will form as a single unique compound a racemic mixture a diastereomeric mixture a mixture of or more stereoisomers 18

5 V. (6 points) Page 5 Predict the product(s) in each of the following reactions, using the information given. f either product forms as a stereoisomeric mixture, draw one and write "+ enantiomer" or "+ diasteromer". s -1pt if "+ enantiomer" "+ enantiomer" + other byproducts 1) abr a single optically active substitution product ) a both products have molecular formula MR: 5 peaks 1 -MR: 10 peaks a + (d) Provide all the missing information for the following transformation. Each reaction should be balanced. Li + Li Li