Asymmetric synthesis using chiral acetals. Studies on the nucleophilic addition of organometallics to chiral. ALPHA.-keto acetals in open-chain systems.

…, M FUJI, T YOSHIDA, R TAKEUCHI, H Fujioka

Index: Tamura, Yasumitsu; Annoura, Hirokazu; Fuji, Masahiro; Yoshida, Takayuki; Takeuchi, Ritsuko; Fujioka, Hiromichi Chemical and Pharmaceutical Bulletin, 1987 , vol. 35, # 12 p. 4736 - 4746

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Citation Number: 30

Abstract

Nucleophilic addition of organometallic reagents (Grignard reagents and organolithium reagents) to three chiral α-keto acetals (1a-c) in open-chain systems was studied. The reactions of the chiral a-keto acetals (1a, 1b) having a chiral auxiliary as a ketone equivalent with Grignard reagents proceeded in a highly diastereoselective manner (> 94% diastereomeric excess (de)). As an application of the reaction, the syntheses of the key ...