Synthesis

… Boron-Mediated anti-Aldol Reactions of 4-Silyl Substituted 2, 2-Dimethyl-1, 3-dioxan-5-one. Diastereo-and Enantioselective Synthesis of Protected Oxopolyols

D Enders, OF Prokopenko, G Raabe, J Runsink

Index: Enders, Dieter; Prokopenko, Oleg F.; Raabe, Gerhard; Runsink, Jan Synthesis, 1996 , # 9 p. 1095 - 1100

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Citation Number: 25

Abstract

The boron enolate of ketone (S)-3 was prepared according to the Evans' protocol (c- Hex2BCl, N, N-dimethylethylamine, diethyl ether, 0 C, 1 h). The subsequent aldol reactions with a variety of aldehydes alforded after oxidative workup (H202, pH 7 buffer/MeOH) the anti-aldol adducts (S, S, S)-4 in 78—93% yield after purification by flash chromatography. No other diastereoisomers of the crude adducts 4 could be detected by TLC. The diaste- ...