'Clip-Cycle' approaches to functionalised pyrrolidines, pyrrolizidines and indolizidines

The 'Clip-Cycle' approach is a versatile and modular synthetic method for the synthesis of aza-heterocycles via sequential cross metathesis and aza-Michael reactions. In this manuscript, a series of innovations to the 'Clip-Cycle' approach are reported. First, the asymmetric 'Clip-Cycle' syntheses of 2,5- and 3,5-pyrrolidines from chiral starting materials are reported for the first time, using a kinetic resolution method. A two-directional 'Clip-Cycle' approach for the synthesis of pyrrolizidines and indolizidines is then introduced.