The intramolecular cycloaddition of azides with ω-chloroalkenes. A facile route to (-)-swainsonine and other indolizidine alkaloids

Article abstract of DOI:10.1016/S0040-4039(00)97301-5

A potentially general route to the 1-azabicyclo[n.m.0]alkane skeleton of various alkaloids is embodied in the intramolecular 1,3-dipolar cycloaddition of aliphatic azides with ω-chloroalkenes. Cycloaddition is followed by rearrangement and intramolecular N-alkylation, affording bicyclic iminium ions 1 in one operation. The application of this method to the synthesis of (±)-δ-coniceine 6, (1S,2R,8aR)-indolizidine-1,2-diol 13 and (-)-swainsonine 15 is described.