Total synthesis of
four callyspongiolide stereoisomers led to unambiguous
assignment of relative and absolute stereochemistry of the natural
product. Key features of the convergent, fully stereocontrolled route
include the use of Krische allylation, Kiyooka Aldol reaction, Kociénski–Julia
olefination, Still–Gennari olefination, Yamaguchi macrocyclization,
and Sonogashira coupling reaction. Biological evaluation of the synthesized
compounds against an array of cancer cells revealed that the stereochemistry
of the macrolactone core played an important role
