Identify the reagents necessary to accomplish each of the following transformations.

Aprepitant (trade name Emend) is used to prevent the acute nausea and vomiting caused by chemotherapy. Identify E and F, intermediates in the synthesis of aprepitant.

What is the major elimination product obtained from the following reaction? Br toons CH3 (CH3)3CO (CH3)3COH CH₂ Of-Bu || CH₂ Of-Bu III CH3 o IV CH3

4. Regioselectivity Draw the major product formed for each reaction. Assume the reactions are irreversible. Include stereochemistry when products contain stereocenter(s). (a) Draw only the substitution product. Both elimination and substitution occur here. Hac Br CH₂OH (c) (b) CH3 CH3 Br H NaOCH3 80 °C 1 equiv CH3Li then