Synthesis of Spirofungin A

Significance

Spirofungin A is a metabolite of Streptomyces violaceuniger Tu 4113 that displays significant antiproliferative activity in a panel of cancer lines and it selectively inhibits isoleucyl-tRNA synthetase in mammalian cells. The synthesis depicted makes elegant use of ring-opening, ring-closing and cross metatheses mediated by Grubbs II catalyst to assemble key fragments. A further asset is the use of a temporary silylacetal tether to fix the stereochemistry of the spiroacetal at C15 in G.