PREPARATION AND REACTIVITY OF CHIRAL BETA-AMIDO-ALKYLZINC IODIDES AND RELATED CONFIGURATIONALLY STABLE ZINC ORGANOMETALLICS

Several zinc organometallics bearing at the beta-position a carbamate or an amido function with an acidic N-H group were prepared using the direct insertion of zinc dust into the corresponding alkyl iodides in THF or THF:DMSO mixtures. Most of the starting iodides were obtained from natural alpha-amino acids and the resulting zinc species afforded after transmetalation with CuCN.2LiCl and reaction with a selection of relatively reactive electrophiles a variety of polyfunctional 1,2-amino alcohol derivatives and carbamates in optically pure form. Several secondary beta-amido alkyl iodides were converted to the corresponding chiral zinc reagents and trapped with electrophiles. The configurational stability of chiral secondary organozinc compounds and the stereochemical course of their reactions were examined.