A Soft Vinyl Enolization Approach to α-Aey!vinyl Anions % Direct Aidol/Aldol Condensation Reactions of (E)-β-CMorovinyl Ketones

摘要

Keto-enol tautomerization is one of the fundamental chemical phenomena that empowers our ability to modulate the reactivity of carbonyl compounds. The enol and metal enolate forms of carbonyl compounds constitute one of the most widely used nucleophiles in the C—C bond forming strategies that readily accommodate various electrophiles as reaction partners. Whereas regio- and stereoselective enol(ate) formation of carbonyl compounds with α-C(sp~3)—H bonds has been achieved with an increasing degree of sophistication, the generation of corresponding enol and enolate forms of carbonyl compounds with α-C(sp2)—H bonds (such as allenol and allenolates) has been limited to a few exceptional cases of α,β-unsaturated carbonyl compounds (Scheme 1).