Steric and Electronic Effects on the Dehydration Step in Cyclohexanone and Bicyclic Ketones Oxime Formation
作者:Ines Maria Costa Brighente、Leonor Rosa Vottero、Alberto Jose Terezani、Rosendo Augusto Yunes
DOI:10.1246/bcsj.66.2289
日期:1993.8
Between pH 4 and pH 13, oxime formation from hydroxylamine with cyclohexanone and bicyclic ketones proceeds with rate limiting dehydration of the addition intermediate which is in equilibrium with the ketone and hydroxylamine. The dehydration step exhibits catalysis by oxonium ion (pH 4 to ca. 8), a pH independent pathway (pH 8 to ca. 10) and catalysis by hydroxide ion (pH ca. 10 to 13). The steric
在 pH 4 和 pH 13 之间,羟胺与环己酮和双环酮的肟形成随着与酮和羟胺平衡的加成中间体的限速脱水进行。脱水步骤表现出氧鎓离子催化(pH 4 至约 8)、pH 独立途径(pH 8 至约 10)和氢氧根离子催化(pH 约 10 至 13)。空间和电子效应为了解氧鎓离子、氢氧根离子催化和自发反应机制的过渡态结构提供了重要见解。