Multicomponent linchpin coupling of silyl dithianes employing an N-Ts aziridine as the second electrophile: synthesis of (-)-indolizidine 223AB.

[reaction: see text] An efficient, stereocontrolled assembly of the indolizidine alkaloid, (-)-indolizidine 223AB, exploiting a three-component linchpin coupling employing an N-Ts aziridine as the second electrophile, followed by a one-pot sequential construction of the indolizidine ring system, has been achieved. The longest linear sequence was 10 steps, proceeding in 10% overall yield.