Exploiting Orthogonally Reactive Functionality: Synthesis And Stereochemical Assignment Of (-)-ushikulide A

摘要

In 2005, Takahashi and co-workers reported the isolation of ushikulide A (1) from a culture broth of Streptomyces sp. IUK-102 (Figure 1). This compound exhibits potent activity against murine splenic lymphocyte proliferation (IC_(50) = 70 nM), rivaling that of the well-known cyclosporin A~2 and FK506, which revolutionized organ transplant therapy by suppressing rejection. Takahashi's structural assignment dealt with connectivity, not stereochemistry, as analysis of 1 by X-ray diffraction proved untenable in this particular case.