Divergent syntheses of resorcylic acid lactones: L-783277, LL-Z1640-2, and hypothemycin.

The resorcylic acid lactones (RAL) are endowed with diverse biological activity ranging from transcription factor modulators (zearalenone and zearalenol) to HSP90 inhibitors (radicicol and pochonin D) and reversible (aigialomycin D) as well as irreversible kinase inhibitors (hypothemycin and other RAL containing a cis-enone). Our interest in broadening the diversity of this family beyond naturally occurring diversity has led us to seek a general approach that could be used to address the entire spectrum of functionalities present within this family. Herein, we present our efforts on accessing macrocycles bearing an alkane, alkene, or epoxide at the benzylic position from a common benzylic sulfide intermediate to access L-783277, LL-Z1640-2, and hypothemycin.