Synthesis of gamma-amino esters via Mn-mediated radical addition to chiral gamma-hydrazonoesters.

Highly stereoselective Mn-mediated couplings of alkyl iodides with chiral N-acylhydrazones bearing ester functionality afford a series of gamma-hydrazino esters, including gamma-substituted, alpha,gamma-disubstituted, and alpha,alpha,gamma-trisubstituted examples. In contrast to prior work with chiral N-acylhydrazones, high stereoselectivity was observed even in the absence of Lewis acid. Microwave-assisted acylation with trifluoroacetic anhydride and reductive N-N bond cleavage provided the gamma-amino ester functionality in a synthetically useful N-TFA-protected form.