Synthesis of the pentacyclic xestobergsterol skeleton

Scalable Synthesis of an Acid Stable Analogue of Hippuristanol

Hippuristanol is a marine derived steroidal natural product with promising anticancer activity. However, instability at low pH has precluded its development as an efficient therapy. We addressed this limitation by replacing one of the oxygen atoms of the spiroketal moiety with a carbon atom. Key steps in the synthesis include a Meyer-Schuster/Nazarov cascade, a hypoiodite mediated oxyfunctionalization, and the late-stage installation of a hydroxyl group on the C-ring of the steroid.

A Facile Synthesis of the Basic Steroidal Skeleton Using a Pauson−Khand Reaction as a Key Step

A high-yield synthesis of steroid-type molecules under mild reaction conditions is achieved in two steps involving nucleophilic addition of alkynyl cerium reagent to an easily enolizable carbonyl compound (beta-tetralone) followed by an intramolecular Pauson-Khand reaction.

The synthesis of functionalized 13,14-seco-steroids via Grob fragmentation

A synthetic methodology for the synthesis of 13,14-seco-steroids with substituents at C-14 and C-17 is described. The approach involves Grob fragmentation of 14beta-hydroxy-17beta-tosylates, hydroboration-oxidation of the intermediate delta13(17)-olefin, and hydride reduction of the 14-ketone. An unambiguous structural assignment of (13R,14S,17S)-14,17-diacetoxy-3-methoxy-7alpha-methyl-13,14-secoestra-1,3,5(10)-triene was determined by X-ray analysis.