Novel syntheses of the carbapenem key intermediates,(3R, 4R)-4-acetoxy-3-[(R)-1-(t-butyldimethylsilyloxy) ethyl]-2-azetidinone and (3S, 4R)-3-[(R)-1-(t- …

…, Y Kobayashi, T Kawabata, M Takase, S Terashima

Index: Ito; Kobayashi; Kawabata; Takase; Terashima Tetrahedron, 1989 , vol. 45, # 18 p. 5767 - 5790

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Citation Number: 97

Abstract

Two types of the carbapenem key intermediates (4 and 6) have been efficiently synthesized from inexpensive (S)-ethyl lactate (7). Thus,(S)-2-benzyloxypropanal readily obtainable from 7 was condensed with di-p-anisylmethylamine to give the chiral imine. The [2+ 2]- cycloaddition reaction of diketene with the imine underwent in a highly stereoselective manner, yielding the desired 3, 4-trans-3-acetyl-β-lactam (13a) as a major product ( ...