Allenyl Enolates - A New Class of Chiral Ambident Nucleophiles, 41: Axis to Center Chirality Transfer in Aldol Reactions of Allenyl Enolates

Abstract

Aldol reactions of the allenyl enolate prepared from ethyl 5,6,6-trimethyl-3,4-heptadienoate (1) and LDA proceed with good diastereofacial selectivity and simple diastereoselection if the lithium enolate is transmetalated with magnesium bromide etherate. This axis to center chirality transfer was utilized in the synthesis of enantiomerically pure ethyl (2R,3S)-4,4-dimethyl-3-hydroxy-2-hydroxymethylpentanoate (7).