. beta.-Lactams. 3. Asymmetric total synthesis of new non-natural 1. beta.-methylcarbapenems exhibiting strong antimicrobial activities and stability against human …

…, Y Nagase, T Kumagai, H Matsunaga…

Index: Nagao, Yoshimitsu; Nagase, Yunosuke; Kumagai, Toshio; Matsunaga, Hiroshi; Abe, Takao; et al. Journal of Organic Chemistry, 1992 ,  vol. 57,  # 15  p. 4243 - 4249

Full Text: HTML

Citation Number: 76

Abstract

Asymmetric synthesis of 11, the precursor to chiral (3R, 4R)-3-[(1R)-1-[(tert- butyldimethyleilyl) oxy] ethyl]-4-acetoxyazetidin-2-one (3) was achieved by utilizing a highly diastereoselective aldol-type reaction of acetaldehyde and the chiral tin (I1) enolate of 5. Similar diastereoselective alkylations of chiral and achiral tin (I1) enolates 13a-d with chiral3 were also performed to obtain the desired alkylated azetidin-2-ones (17a-d). Compounds ...