GENERATION AND CYCLOADDITIONS OF 2-(N-ACYLAMINO)-1-THIA-1,3-DIENES. STRUCTURAL INVESTIGATIONS USING NMR METHODS. PART I.

Article abstract of DOI:10.1016/S0040-4020(01)89147-X

A method has been developed for the efficient generation of 2-(N-acylamino)-1-thia-1,3-dienes.These novel hetero-dienes, which are generated via acylation of the corresponding thioamides, undergo irreversible regio- and stereospecific Diels-Alder addition to the starting thioamides to yield 6-(N-acylamino)-3,4-dihydro-2H-thiopyrans.The regiochemistry, relative configurations and the major solution conformations of the thiopyrans 4a-c and 10 have been determined using NMR techniques.In addition, it has been found that these systems exhibit a number of unique physical and chemical properties.