An Expeditious Route to 1α,25-Dihydroxyvitamin D<sub>3</sub>and Its Analogues by an Aqueous Tandem Palladium-Catalyzed A-Ring Closure and Suzuki Coupling to the C/D Unit
mild, general, and highly stereoselectivePd0‐catalyzed cascade to the triene system of the hormone 1α,25‐dihydroxyvitamin D3 and six representative analogues is reported. The intramolecular cyclization of an enol–triflate (lower fragment) followed in situ by Suzuki–Miyaura coupling with an alkenyl boronic ester (upper fragment, also efficiently prepared by Pd0‐catalyzed coupling) in equimolar amounts
Efficient Convergent Synthesis of 1α,25-Dihydroxyvitamin D<sub>3</sub> and Its Analogues by Suzuki−Miyaura Coupling
作者:Takeshi Hanazawa、Akiko Koyama、Takeshi Wada、Eiko Morishige、Sentaro Okamoto、Fumie Sato
DOI:10.1021/ol0274007
日期:2003.2.1
[reaction: see text] 1alpha,25-Dihydroxyvitamin D(3) was synthesized by the Suzuki-Miyaura coupling of the A-ring intermediate 1, which was efficiently prepared from readily available 1,7-enyne 2, with the corresponding boronate compound of the C,D-ring portion. The method was applied to prepare des-C,D analogues of 1alpha,25-dihydroxyvitamin D(3).