Regio- and stereoselective Heck arylations of N-carbomethoxy-L- 3-dehydroproline methyl ester with arenediazonium salts. Total synthesis of neuroexcitatory aryl kainoids

The Heck arylation of N-carbomethoxy-L-3-dehydroproline methyl ester with arenediazonium tetrafluoroborates produced chiral 4-aryldehydroproline derivatives in moderate to good yields in a highly regio- and stereocontrolled fashion. A rationale for the unexpected high regioselectivity is provided using Deeth's model. Heck adduct 15 (G = o-CH3O) was converted into several aryl kainoids using concise and efficient routes.