Stereoselective synthesis of naturally-occurring 7-(hetero)aryl(2E,4E,6E)-2,4,6-heptatrienamides and their structural analogs

A new and efficient highly stereoselective method to prepare naturally-occurring 7-(hetero)aryl (2E,4E,6E)-2,4,6-heptatrienamides and their structural analogues has been developed. The physical and spectral properties of one of these compounds, i.e. (2E,4E,6E)-7-(2-thienyl)-2,4,6-heptatrienoic acid piperidide (4 b), have been found to be quite different from those previously reported for 7-(2-thienyl)-2,4,6-heptatrienoic acid piperidide isolated from Othantus maritimus to which the (2E,4E,6E)-configuration had been previously assigned.