Synthetic Development of Radicicol and Cycloproparadicicol: Highly Promising Anticancer Agents Targeting Hsp90
Samuel J. Danishefsky, Xudong Geng, Zhiqiang Yang · Synlett · 2004
Molecular chaperone Hsp90 has emerged as one of the most exciting new targets for anticancer therapy. Natural product-based modulators, such as radicicol (1), inhibit Hsp90 and induce the breakdown of its client proteins, thereby blocking multiple critical oncogenic pathways. Several total synthesis endeavors directed toward radicicol have been accomplished. Cycloproparadicicol (2), a potent Hsp90 inhibitor and highly promising pre-clinical anticancer agent, was discovered through a convergent total synthesis approach. In an effort to devise a more efficient and concise route to reach 2, a novel ‘ynolide’ protocol, featuring an ynolide-bissiloxydiene Diels-Alder addition, was designed and reduced to practice. This methodology was also extended to aigialomycin D.