Total Synthesis of Phalarine

摘要

Our research group has been addressing the total synthesis of an alkaloid, phalarine (1), with an unusual structure. Pursuant to this goal, in the previous Communication we described a novel rearrangement of an azaspiroindolenine 3 (derived from 2) to a prototype precursor 4 to phalarine (Scheme 1).[1] Some interesting mechanistic issues associated with this rearrangement were elucidated and we assumed that a total synthesis of 1 would be a straightforward matter. As described below, we were indeed able to accomplish the inaugural total synthesis of phalarine using the rearrangement strategy, although significant obstacles had to be overcome.