Retardation of AlH<sub>2</sub>Cl Hydrogenolysis of the Ethylene Ketals of 5-Norbornen-2-one and 2-Norbornen-7-one Due to the Presence of the Double Bond
作者:H. A. Davis、R. K. Brown
DOI:10.1139/v73-052
日期:1973.2.1
bond in either 5-norbornen-2-one ethylene ketal or 2-norbornen-7-one ethylene ketal provides no anchimeric assistance in the hydrogenolysis of these ketals by AlH2Cl in ether. Instead, a marked retardation of reaction occurs, a result considered to be due to competitive association of the Lewis acid, AlH2Cl, with the π bond.Attack of the AlH2Cl on the former ketal occurs from the exo direction to give
5-norbornen-2-one 乙烯缩酮或 2-norbornen-7-one 乙烯缩酮中的双键在这些缩酮被 AlH2Cl 在乙醚中的氢解过程中不提供嵌合辅助。相反,发生了明显的反应延迟,这一结果被认为是由于路易斯酸 AlH2Cl 与 π 键的竞争性缔合。AlH2Cl 对前缩酮的攻击从外向方向发生,仅产生内向 5 -β-羟基乙氧基产物,而后一种缩酮与 AlH2Cl 反应生成顺式和反式 7-β-羟基乙氧基产物的 2:1 混合物。提供了解释结果的基本原理。