( E)- N-Isopropyl-5-tosyl-4-pentenamide: A vinyl sulfone as precursorv of a new δ-acyldienyl anion equivalent

Abstract

( E)- N-Isopropyl-5-tosyl-4-pentenamide ( 7b), prepared from 4-pentenoic acid by stereoselective iodosulfonylation-dehydroiodination and further amidation with oxalyl chloride and isopropylamine, reacts with two equiv of n-butyllithium at −78°C and then with aldehydes affording stereoselectively (2 E,4 E)-6-hydroxy-2,4-hexadienamides 9. In the case of carboxylic acid chlorides or cyclohexyl isocyanate, dilithiated lactam 8c undergoes acylation to afford the corresponding lactam derivatives 10.