Regioselectivity of 1,3-dipolar cycloaddition of 3-oxidopyridinium betaines to olefins and stereoselective synthesis of 6-alkyloxy-5-oxa-9- azatricyclo[5.2.1.04,8]decan-2-one derivatives
A new method to obtain the four isomers of tropane skeleton by dipolar addition of 3-oxidopyridinium betaines to activated olefins is described, and a general synthetic strategy for tricyclic tropane homologues is also reported.