Progress toward the total synthesis of psymberin/irciniastatin A

In this paper, we describe our synthesis of four key building blocks for the total synthesis of psymberin (1) and its C4 epimer (2). Despite early difficulties in processing material to the advanced intermediate stage, we have been successful in developing high-yielding syntheses for the pyran core, natural side chain, 4-epi side chain, and aryl fragments of the molecule. Our findings from the optimization process are presented herein.