REDUCTIVE ROUTES TO RIGID PEPTIDE BUILDING-BLOCKS - THE DEPENDENCE OF A REGIOSELECTIVE IMIDE REDUCTION ON THE NATURE OF AN ALPHA-ALKOXY SUBSTITUENT

The reduction of several N-acylpyrrolidinones has been studied. The regioselectivity of the reductions was found to depend on the nature of the N-acyl group. In one example, the use of a sterically bulky triisopropylsiloxy substituent alpha to the N-acyl carbonyl led to exclusive reduction of the pyrrolidinone carbonyl and the formation of a product that could be used in the synthesis of the 1-azabicyclo[5.3.0]decane ring skeleton found in a key bicyclic Pro-Phe building block.