A formal [3+2] cycloaddition process with nonactivated aziridines to polysubstituted indolizidines.

[chemical reaction: see text]. Heating a mixture of ethyl 7-iodo-2-heptynoate (or its analogues), 2-aryl aziridines, and K2CO3 in dry CH(3)CN delivers polysubstituted indolizidines. This reaction goes through an S(N)2/formal [3+2] cycloaddition process and represents the first synthetically useful example of the formal [3+2] cycloaddition process through a C-N bond cleavage of nonactivated aziridines.