An Efficient Sequential Reaction Process to Polysubstituted Indolizidines and Quinolizidines and Its Application to the Total Synthesis of Indolizidine 223A

[GRAPHICS] The reaction of iodides 1 with delta-chloropropylamines 5 in MeCN assisted with K2CO3 undergoes a sequential S(N)2/Michael addition/S(N)2/S(N)2 reaction process to give polysubstituted indolizidines and quinolizidines. Using this method, indolizidine 223A is synthesized from 2-ethyl-2-hexenoic acid in 12 linear steps and 14.5% overall yield.