A TiCl4-promoted domino semipinacolâSchmidt reaction of oxaspiropentane-azide provides an easy access to bridged azatricyclic ring systems, which possess the azaquaternary center, present in the immunosupressant FR901483 and platelet aggregation inhibitor daphlongeranine B.
通过 TiCl4 促进的多米诺半联苯酚施密特反应,可以很容易地获得桥接的氮杂环系统,该系统具有氮杂四元中心,存在于免疫抑制剂 FR901483 和血小板聚集抑制剂达夫龙葵碱 B 中。
Asymmetric Total Synthesis of Brasiliquinones B and C via Oxidative Cyclization of a Hydroquinone-Silyl Enol Ether Hybrid
作者:Hiroki Miyake、Ryo Nakajima、Takuya Kumamoto
DOI:10.1021/acs.joc.2c01653
日期:2022.9.16
The asymmetric total synthesis of angucycline antibiotics (S)-brasiliquinones B and C was accomplished. The benz[a]anthraquinone core was constructed via oxidative cyclization of a hydroquinone-silyl enol ether hybrid. The resultant pentacyclic acetal was converted to the silyl enol ether, which was treated with Pd(II)/O2 to afford brasiliquinone C, after multistep conversion including dehydrogenation
完成了角环素类抗生素( S )-巴西醌B和C的不对称全合成。苯并[ a ]蒽醌核心是通过对苯二酚-甲硅烷基烯醇醚杂化物的氧化环化构建的。将所得五环缩醛转化为甲硅烷基烯醇醚,经多步转化(包括脱氢、去甲硅烷化和脱缩醛化以及对苯二酚氧化)后,将其用 Pd(II)/O 2处理得到巴西硅醌 C。基于与合成产物的立体化学相关性,证实了天然巴西醌的 ( S )-构型。