Novel Intramolecular [4 + 1] and [4 + 2] Annulation Reactions Employing Cascade Radical Cyclizations
作者:Kiyosei Takasu、Hiroshi Ohsato、Jun-ichi Kuroyanagi、Masataka Ihara
DOI:10.1021/jo0258397
日期:2002.8.1
silane promote sequential/cascade free radical cyclization reactions of dienoate tethered vinyliodides or alkynes. These processes produce [4 + 1] and [4 + 2] annulated products. In contrast, the electrochemical reductions of the vinyliodides afford monocyclic compounds. Both the regiochemical and stereochemical courses of the sequential radical cyclizations strongly depend on substrate structure.
氢化三丁基锡和三(三甲基甲硅烷基)硅烷可促进二烯酸酯系链的乙烯基碘或炔烃的顺序/级联自由基环化反应。这些过程产生[4 +1]和[4 + 2]环形产品。相反,乙烯基碘的电化学还原得到单环化合物。顺序自由基环化的区域化学过程和立体化学过程都强烈取决于底物结构。特别重要的是在空间和立体电子(鲍德温法则)之间的平衡,以控制环化区域化学。