(b) One possible alkene product is shown in the reaction above. Draw the other alkene product that could form from a modified Wittig, the Horner-Emmons reaction (p387). (c) What was your aldehyde starting material? (What is "R"?)

iv. Why is the product shown the preferred constitutional isomer of this reaction? Br₂/MeOH OMe Br (A) The nucleophile attacks the more stable carbocation formed during Markovnikov addition (B) The nucleophile attacks the carbon with the largest + charge (C) Steric hindrance inhibits the nucleophilic attack on the other carbon (D) The bromonium bridge forces an anti-addition of the nucleophile.

Question 1. Draw (as you see it below) the given mechanism for the following SN2 reaction in ChemDraw. EPIN Na Co : OCH3 Lan CH3 NaCl

Draw a structural formula for the more stable carbocation intermediate formed in the reaction shown. CH3CH2 CH₂CH₂CH3 H H + HI • You do not have to consider stereochemistry. • Do not include anionic counter-ions, e.g., I, in your answer. • For cases in which carbocations of the same or similar stability are expected, draw all of the structures. • Draw one structure per sketcher. Add additional sketchers using the drop-down menu in the bottom right corner. Separate structures with + signs from the drop-down me menu. ChemDoodleⓇ [ ] در > Previous Ne:

2. Write out every step of the following reactions, indicating which mechanism(s) will be favored. Include all steps (e.g. carbocation formation) and make final products neutral (e.g. R-OH, not R-OH₂). Show stereochemistry. For eliminations with more than one possible alkene product, draw only the major product. (Zaitsev Rule!) You don't have to show curved arrows. + :OCH, +OC(CH₂) DMF DMF