Abstract
Herein, we report a concise chemoenzymatic synthesis of the cardenolide rhodexin A in 9 steps and the first protecting-group-free synthesis of its aglycone sarmentogenin in 7 steps from 17-deoxycortisone. The synthesis features a scalable enzymatic C(14)-H α-hydroxylation, a Bestmann ylide-enabled one-step construction of the butenolide motif, a late stage Mukaiyama hydration, and a stereoselective C11 carbonyl reduction.