Use of lithium (α-methylbenzyl)allylamide for a formal asymmetric synthesis of thienamycin

Abstract

The highly stereoselective conjugate addition of lithium (αR)-(α-methylbenzyl)allylamide 3 to (E)-tert-butyl penta-2,4-dienoate 4, followed by a stereoselective aldol reaction with acetaldehyde, are the key steps in the synthesis of the known β-lactam intermediate, (3S,4R)-3-[(R)-1-(tert-butyldimethyls ilyloxy)ethyl]-4-vinylazetidin-2-one 2, for elaboration to thienamycin and its derivatives.