New Chiral Synthesis of Methyl and Allyl Disubstituted Butyrolactone: A Formal Synthesis of (-)-Ngaione
作者:Kohei Inomata、Katsufumi Suzuki、Yasuyuki Endo
DOI:10.3987/com-03-9908
日期:——
A new chiral synthesis of butyrolactone [(-)-7] bearing methyl and allyl substituents at the γ-position has been established via diastereoselective continuous nucleophilic addition to the chiral tricyclic lactone [(-)-1] as the key step. In practice, continuous nucleophilic addition to the tricyclic lactone [(-)-1] by using the combination of methyllithium and allylmagnesium bromide proceeded to yield
以手性三环内酯[(-)-1]的非对映选择性连续亲核加成为关键步骤,建立了在γ位具有甲基和烯丙基取代基的丁内酯[(-)-7]的新手性合成方法。在实践中,通过使用甲基锂和烯丙基溴化镁的组合对三环内酯[(-)-1]进行连续亲核加成,可以非对映选择性地产生相应的二醇(8)。8氧化后,通过逆Diels-Alder反应得到对映纯甲基和烯丙基二取代丁烯内酯(10)。10 的选择性1,4-还原得到相应的丁内酯[(-)-7],它是(-)-ngaione 合成的关键中间体。