A deconjugative alkylation/Diels-Alder cycloaddition strategy to synthesize 2-substituted bicyclic scaffolds
作者:Wei Zhang、Ion Ghiviriga、Alexander J. Grenning
DOI:10.1016/j.tet.2016.11.055
日期:2017.7
Knoevenagel adducts derived from α,β-unsaturated aldehydes and a malonic acid derivative can undergo deconjugative alkylation using dienophile-functionalized alkyl iodides. The single step reaction is two-fold significant: (a) The electron-deficient diene (α,β-unsaturated aldehyde Knoevenagel adduct) is deconjugated from the esters, resulting in an electronically neutral diene and (b) tethers the diene
衍生自α,β-不饱和醛和丙二酸衍生物的Knoevenagel加合物可以使用亲双烯体官能化的烷基碘进行去共轭烷基化。一步反应有两个重要意义:(a)酯中解离缺电子的二烯(α,β-不饱和醛Knoevenagel加合物),生成电子中性的二烯,以及(b)束缚二烯和亲二烯体,它们允许分子内环加成到在2-位带有丙二酸衍生物的双环系统。因此,该序列将简单的试剂转化为天然产物相关的双环支架。我们还公开了由于丙二酸酯在2-位的位置而导致的意想不到的Diels-Alder环加成/芳族CC裂解反应。