Diastereoselective Synthesis of Functionalised 5-Amino-3,4-Dihydro-2H-Pyrrole-2-Carboxylic Acid Esters: One-Pot Approach Using Commercially Available Compounds and Benign Solvents.

Abstract

A novel three-step four-transformation approach to highly functionalised 5-amino-3,4-dihydro-2H-pyrrole-2-carboxylic acid esters, starting from commercially available phenylsulfonylacetonitrile, aldehydes and N -(diphenylmethylene)glycine tert -butyl ester, was developed. Our one-pot strategy delivers this class of amidines bearing, for the first time, three contiguous stereocenters, in good to high yield and diastereoselectivity. The entire sequence has been carried out using diethyl carbonate and 2-methyl tetrahydrofuran as benign solvents, operating under metal-free conditions. The process can be conveniently scaled-up and the synthetic utility of the products was demonstrated.A novel three-step four-transformation approach to highly functionalised 5-amino-3,4-dihydro-2H-pyrrole-2-carboxylic acid esters, starting from commercially available phenylsulfonylacetonitrile, aldehydes and N-(diphenylmethylene)glycine tert-butyl ester, was developed. Our one-pot strategy delivers this class of amidines bearing, for the first time, three contiguous stereocenters, in good to high yield and diastereoselectivity. The entire sequence has been carried out using diethyl carbonate and 2-methyl tetrahydrofuran as benign solvents, operating under metal-free conditions. The process can be conveniently scaled-up and the synthetic utility of the products was demonstrated.