Highly diastereoselective additions of methoxyallene and acetylenes to chiral α-keto amides

Abstract

α-Keto amides bearing (S)-indoline chiral auxiliaries reacted with lithiated methoxyallene or lithium acetylides to produce the corresponding dihydrofuranones 7 through formation of the tertiary α-hydroxy allenes, or tertiary α-hydroxy acetylenes, respectively, at −78 °C with high diastereoselectivities (up to >99% de).