Allylindation of Cyclopropenes Stereochemically Regulated by the Chelation

本文系统地研究了烯丙基试剂（烯丙基化）与环丙烯及含羟基化合物加成反应中羟基对反应活性和选择性的螯合作用。在3位上带有羟基的环丙烯很容易与烯丙基试剂螯合，使烯丙基化产物具有高度的区域选择性和立体选择性。在环丙烯与1位羟基烷基的烯丙基化反应中，选择性很大程度上取决于羟基烷基链的长度。因此，发现选择性被羟基的位置所改变。此外，改变烯丙lindium试剂和反应溶剂可以很好地调节选择性。烯丙基化产物环丙基的结构已经用x射线晶体学进行了全面表征。具有张力碳碳双键的降冰片烯醇衍生物也经历了干净的烯丙基化，其中羟基加速了烯丙基化，并控制了高的区域选择性和立体选择性。

The chelation effects of a hydroxy group on the reactivities and selectivities have systematically been studied in the addition reactions of allylindium reagents (allylindation) to cyclopropenes and related compounds possessing a hydroxy group.The cyclopropenes bearing a hydroxy group in the 3-position chelate readily to allylindium reagents giving allylindation products highly regio- and stereoselectively. In the allylindation of the cyclopropenes with a hydroxyalkyl group at the 1-position, the selectivities depend largely on the length of the hydroxyalkyl chain. Thus, the selectivities are found to be switched by the location of the hydroxy group. Further, changing the allylindium reagents and the reaction solvents nicely regulated the selectivities. The structure of the allylindation product, cyclopropylindium, has fully been characterized by X-ray crystallography.Norbornenol derivatives possessing a strained carbon-carbon double bond also underwent clean allylindation, where the hydroxy group accelerates the allylindation as well as controls high regio- and stereoselectivities.