A general, stereoselective synthesis of 4, 5-disubstituted imidazolidines-2-ones from α- aminoacids has been developed: the key steps are a Blaise reaction of bromoacetate on α- aminonitriles and further reduction. Although reduction with sodium cyanoborohydride afforded a mixture of cis and trans isomers 6a-e with moderate to good stereoselectivity, reduction with sodium in liquid ammonia gave the trans isomers 8a-e with complete ...
