A Concise, metathesis based approach to construction of the lepadiformine/cylindricine tricyclic framework

A tandem dienyne metathesis based strategy has been developed for construction of the core tricyclic framework found in the lepadiformine and cylindricine alkaloids. 2-Pentenyl-2-ethynylpyrollidine acrylamide that serves as the starting material for the key ruthenium carbene catalyzed metathesis process is prepared by using a concise route starting with l-proline.