. beta.-Lactams from ester enolates and silylimines: enantioselective synthesis of the trans-carbapenem antibiotics (+)-PS-5 and (+)-PS-6

P Andreoli, G Cainelli, M Panunzio…

Index: Andreoli, Patrizia; Cainelli, Gianfranco; Panunzio, Mauro; Bandini, Elisa; Martelli, Giorgio; Spunta, Giuseppe Journal of Organic Chemistry, 1991 , vol. 56, # 21 p. 5984 - 5990

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Citation Number: 51

Abstract

A new synthetic route to the antibiotics (+)-PS-5 and (+)-PS-6 is described. The preparation involves a fully stereocontrolled reaction between the enantiomerically pure N- trimethylsilylimine of lactic or mandelic aldehyde and the lithium enolate of the tert-butyl butanoate or tert-butyl isovalerate, respectively. Conversion of the azetidinones obtained to 4-acetoxy derivatives via oxidative cleavage of the hydroxyethyl or hydroxybenzyl side ...