Diastereoselective Production of Homoallylic Alcohols Bearing Quaternary Centers from γ-Substituted Allylic Indiums and Ketones

Highly stereoselective In-employed addition of γ-substituted
allylic halides (cyclohexenyl halides, cinnamyl halides, and
ethyl 4-bromocrotonate) to ketones is established to produce
homoallyl alcohols bearing quaternary centers. The reactivity
patterns and relative stability of allylic indiums were studied.
The addition of water characteristically affected the reactions.
Cyclohexenyl indium addition was completely disturbed, but
a clear reaction was observed in the cinnamyl and crotonate-indium addition. In the case of ethyl 4-bromocrotonate, an
interesting conversion of a γ-adduct into an α-adduct was
observed in anhydrous conditions.