The Palladium-Catalyzed Aerobic Kinetic Resolution of Secondary Alcohols: Reaction Development, Scope, and Applications
作者:Davidâ C. Ebner、Jeffreyâ T. Bagdanoff、Ericâ M. Ferreira、Ryanâ M. McFadden、Danielâ D. Caspi、Raissaâ M. Trend、Brianâ M. Stoltz
DOI:10.1002/chem.200902172
日期:2009.12.7
and tert‐butyl alcohol greatly enhances reaction rates, promoting rapid resolutions. The use of chloroform as solvent allows the use of ambient air as the terminal oxidant at 23 °C, resulting in enhanced catalyst selectivity. These improved reaction conditions have permitted the successful kineticresolution of benzylic, allylic, and cyclopropyl secondary alcohols to high enantiomeric excess with good‐to‐excellent
已经开发出第一个钯催化的仲醇对映选择性氧化反应,利用容易获得的二胺(-)-金雀花石作为手性配体,分子氧作为化学计量氧化剂。关于碱基和氢键供体作用的机制见解导致了对原始系统的一些改进。也就是说,碳酸铯和叔丁醇的添加大大提高了反应速率,促进了快速分辨率。使用氯仿作为溶剂允许在 23 °C 下使用环境空气作为终端氧化剂,从而提高催化剂选择性。这些改进的反应条件使得能够以良好至优异的选择性因子成功地将苄基、烯丙基和环丙基仲醇动力学拆分为高对映体过量。该催化剂体系也已应用于内消旋二醇的去对称化,提供高产率的对映体富集的羟基酮。
New Reagents for the Synthesis of Arylmethyl Ethers and Esters
作者:Gregory Dudley、Philip Albiniak
DOI:10.1055/s-0029-1219531
日期:2010.4
developmentof new arylmethyl transfer (benzylation) reagents for protectingoxygen functional groups under relatively mild and neutral conditions.It begins with an investigation of organosiletanes as surrogatehydroxyl groups, which inspired siletane-functionalized benzyl ethersand forced us to confront the difficulties associated with the synthesisof benzyl ethers. The end result is a new series of neutral oxypyridiniumsalts
Synthesis of para-methoxybenzyl (PMB) ethers under neutral conditions
作者:Ernest O. Nwoye、Gregory B. Dudley
DOI:10.1039/b617926f
日期:——
2-(4-Methoxybenzyloxy)-4-methylquinoline reacts with methyl triflate in the presence of alcohols to generate a neutral organic salt that transfers the para-methoxybenzyl (PMB) protecting group onto alcohols in high yield and under mild conditions.