Synthesis of the C21-C34 Segment of Aplyronine A toward Its Scalable Preparation.

The development of scalable synthesis of the C21-C34 segment, a key intermediate for aplyronine A and its analogs, is reported. Marshall propargylation and Noyori asymmetric hydrogen transfer served as key reactions for the stereoselective construction of the desired C21-C34 segment on a gram scale. Further transformation of the segment successfully afforded the side chain analog that exhibited actin depolymerization activity similar to that previously reported.