Combining two-directional synthesis and tandem reactions: new access to 3,5-disubstituted pyrrolizidines and first total synthesis of alkaloid cis-223B.

Two new tandem reactions for the synthesis of 3,5-disubstituted pyrrolizidines and the first total synthesis of alkaloid cis-223B (in 7 steps and 43% overall yield), involving a double cross metathesis and double Michael addition as key steps, are presented.