( E)-5-tosyl-4-pentenamide: A vinyl sulfone for the one-pot general synthesis of indolizidine derivatives

Abstract

( E)-5-tosyl-4-pentenamide ( 3), easily prepared from 4-pentenoic acid by stereoselective iodosulfonylation-dehydroiodination and further amidation with oxalyl chloride and ammonia, reacts with sodium hydride at room temperature in DMF and then with 1,3-dielectrophiles such as 1,3-dihalides and α,β-unsaturated esters to provide stereoselectively differently substituted indolizidines 6.