A route to the 9,10-secosteroid astrogorgiadiol featuring a key sp2–sp3 Suzuki type cross-coupling

The described semi-synthetic route differs from the previously published approaches by an original C-7–C-8 disconnection. The kinetic enol triflate of Grundmann ketone was chosen as the CD-ring platform on which to couple an A-ring synthon via a challenging sp2–sp3 cross-coupling. A range of A-ring synthons was synthesized to allow the investigations of various conditions of metal-catalyzed couplings. Suzuki-type chemistry provided a useful (89% yield) answer. Whereas the last step of the designed route—a regioselective opening of the epoxide obtained from the alkene, product of the coupling reaction—proved more challenging than expected, a hydroboration endgame route completed a formal synthesis of (−)-astrogorgiadiol.

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