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

Article abstract of DOI:10.1016/0040-4039(96)00399-1

(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 (2E,4E)-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.