Combinatorial synthesis of nicotine analogs using an Ugi 4-CR/cyclization-reduction strategy.

A practical one-pot synthesis of nicotine analogs from Ugi 4-CR/propargyl adducts is reported. This methodology allows the rapid construction of the pyrrolidine moiety present in nicotine through an intramolecular base-promoted 5-endo cycloisomerization process, followed by a reduction of the resulting mixture of 2- and 3-pyrrolines to afford nicotine analogs in good overall yields.