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Communication | Special issue | Vol 72, No. 1, 2007, pp.103-110
Published online, 28th November, 2006
DOI: 10.3987/COM-06-S(K)9
Stereoselective Mannich-Like Reactions of Ester Enolates Generated on Sugar Templates: A Novel Access to a Key Intermediate for 1β-Methylcarbapenem Synthesis

Daisuke Sasaki, Daisuke Sawamoto, Ken-ichi Takao, Kin-ichi Tadano,* Masayuki Okue, and Keiichi Ajito

*Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Hiyoshi, Kohoku-ku Yokohama 223-8522, Japan

Abstract

The Mannich-like reactions of the enolates generated from 2,3-di-O-protected 6-deoxy-4-O-propionyl-α-D-glucopyranosides with (3R,4R)-4-acetoxy-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]azetidin-2-one were investigated. The corresponding 2,3-di-O-methyl derivative provided the Mannich adduct in good to excellent stereoselectivity. From the major adduct, the azetidin-2-one incorporating an α-methyl acetic acid side chain at the C-4 position with β-configuration was obtained by alkaline hydrolysis. This product, (3S,4S)-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-4-[(R)-1-carboxyethyl]azetidin-2-one, is a useful intermediate for the 1β-methylcarbapenem synthesis.