Stereoselective Sequential Spirocyclopropanation/Cloke–Wilson Rearrangement Reactions for Synthesis of <i>trans</i>-β,γ-Disubstituted γ-Butyrolactones Using Alkylidene Meldrum’s Acid and Benzyl Halides
作者:Minli Zhang、Tong Li、Chaoxing Cui、Xixi Song、Junbiao Chang
DOI:10.1021/acs.joc.9b02978
日期:2020.2.21
spirocyclopropanation/Cloke-Wilson rearrangement reactions have been developed to synthesize γ-butyrolactones using alkylidene Meldrum's acids and benzyl halides. The DBU-promoted spirocyclopropanation was carried out efficiently at room temperature to generate trans-isomeric spirocyclopropyl Meldrum's acid, and the following stereospecific thermal decarboxylative Cloke-Wilson rearrangement afforded trans-γ-butyrolactones
已经开发了立体选择性顺序螺环丙烷化/ Cloke-Wilson重排反应以使用亚烷基梅德鲁姆酸和苄基卤化物合成γ-丁内酯。在室温下有效地进行DBU促进的螺环丙烷化反应,生成反式异构的螺环丙基Meldrum酸,随后进行立体定向热脱羧Cloke-Wilson重排,得到反式γ-丁内酯。可以耐受多种芳香族和脂肪族Meldrum酸衍生的烯烃和苄基卤化物。生产了各种反式-β,γ-二取代的γ-丁内酯,总收率中等至良好,为46%至96%,非对映选择性极好。