A Chiron Approach to the Total Synthesis of (?)-Juglomycin A, (+)-Kalafungin, (+)-Frenolicin B, and (+)-Deoxyfrenolicin

摘要

A general, efficient, and common strategy fornthe synthesis of (−)-juglomycin A, (+)-kalafungin, (+)-frenolicinnB, and (+)-deoxyfrenolicin is reported here. The strategyninvolves the synthesis of a key building block alkyne from ancheap chiral pool material, D-glucono-δ-lactone, Dötznbenzannulation, oxa-Pictet-Spengler reaction, and H2SO4-nmediated epimerization.