Total Synthesis of (−)-Spirotryprostatin B and Three Stereoisomers

Heck cyclization and trapping of the resultant η3-allylpalladium intermediate by a tethered diketopiperazine is the central step in a new stereocontrolled route to spirotryprostatin alkaloids. The versatility of this approach is illustrated by the enantioselective total syntheses of the fungal natural product (−)-spirotryprostatin B (1) and three stereoisomers.