Question

3) Gilman reagents are a type of organocuprate which are able to provide nucleophilic carbons for a 1,4 conjugated addition on a,B-unsaturated carbonyls (see below). Following the addition, an acidic workup protonates the anionic intermediate to yield the product shown. a. Draw the mechanism that occurs between the anionic carbon nucleophile and the cyclic ketone electrophile. The mechanism should use 3 arrows. Show the intermediate following the addition in the box below. Indicate charges Explain why the nucleophilic carbon attacks at carbon 4. b. c. (CH3CH2)CuLi Gilman Reagent Hsc-CH2 (Nucleophilic portion of the Gilman Reagent)

Answer 1

Gilmann Reagent participates in conjugate addition with unsaturated carbonyl compounds.

Gilmann's reagent is the source for Nucleophile which attacks the beta carbon atom of Enone since beta carbon is Electrophilic in nature due resonance between ketone and alkene double bond. Hence Nucleophile will attacks at carbon 4(beta carbon to carbonyl group).