β- and γ-lactams by nickel powder mediated 4-exo or 5-endo radical cyclisations. A concise construction of the mesembrine skeleton
作者:Jérôme Cassayre、Béatrice Quiclet-Sire、Jean-Baptiste Saunier、Samir Z. Zard
DOI:10.1016/s0040-4020(97)10204-6
日期:1998.2
N-Alkenyl trichloroacetamides, upon treatment with nickel powder and acetic acid in refluxing 2-propanol undergo reversible 4-exo radical cyclisation. The cyclised radical can be trapped in different ways leading to β-lactams. When the trap is omitted or not efficient enough, unusual irreversible 5-endo cyclisation occurs affording functionalised five-membered lactams. Synthesis of bicyclic γ-lactams
在回流的2-丙醇中用镍粉和乙酸处理后,N-烯基三氯乙酰胺经历可逆的4-外基自由基环化。环化的自由基可以不同的方式被捕获,从而生成β-内酰胺。如果忽略捕集阱或捕集阱效率不高,则会发生异常的不可逆的5内酯环化反应,从而提供功能化的五元内酰胺。还研究了双环γ-内酰胺的合成,只需几个步骤即可获得Sceletium生物碱骨架。