Gram-Scale Synthesis of (+)-Spongistatin 1: Development of An Improved, Scalable Synthesis of the F-Ring Subunit, Fragment Union, and Final Elaboration

In a quest to develop an effective, scalable synthesis of (+)-spongistatin 1 (1), we devised a concise, third-generation scalable synthesis of (+)-7, the requisite F-ring tetrahydropyran aldehyde, employing a proline-catalyzed cross-aldol reaction. Subsequent elaboration to (+)-EF Wittig salt (+)-3, followed by union with advanced ABCD aldehyde (−)-4, macrolactonization and global deprotection permitted access to >1.0 g of totally synthetic (+)-spongistatin 1 (1).