This paper reports the chemical details of our total synthesis of dl-cephalotaxine (1) and the completion of the first total synthesis of dl-11-hydroxycephalotaxine (3) and dl-drupacine (4). Key steps in the synthesis of dl-cephalotaxine include: (1) conjugate addition/alkylation of aryllithium to vinyl sulfone to afford adduct 24C, bearing the entire carbon assemblage; (2) self-immoliative elimination of homoallyl 24C to exocyclic diene 25 via treatment with t-BuLi; (3) establishment of the tetracyclic array by an intramolecular Diels-Alder reaction of an acylnitroso moiety to an exocyclic diene

中文翻译：

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通过乙烯基砜合成。38. 三尖杉生物碱 dl-cephalotaxine、dl-11-hydroxycephalotaxine 和 dl-drupacine 的全合成

本文报道了我们全合成 dl-cephalotaxine (1) 的化学细节以及完成了 dl-11-hydroxycephalotaxine (3) 和 dl-drupacine (4) 的首次全合成。dl-头孢噻肟合成的关键步骤包括： (1) 芳基锂与乙烯基砜的共轭加成/烷基化得到加合物 24C，带有整个碳组合；(2)通过t-BuLi处理自焚消除高烯丙基24C生成环外二烯25；(3) 通过酰基亚硝基部分与环外二烯的分子内 Diels-Alder 反应建立四环阵列