Mechanistic Investigations of a Stable, Highly Active, Extremely Sterically Shielded Molecular Gold Catalyst
作者:Simone G. Weber、David Zahner、Frank Rominger、Bernd F. Straub
DOI:10.1002/cctc.201200944
日期:2013.8
An N‐heterocyclic carbene gold complex IPr**AuNTf2 has been synthesized, spectroscopically investigated, structurally characterized, and used as a highly active and stable catalyst in the Hashmi phenol synthesis (IPr**=1,3‐di‐p‐tolylimidazol‐2‐ylidene with four di‐tert‐butylbenzhydryl ortho substituents, Tf=trifluoromethansulfonyl). A side reaction comprises an irreversible arene oxide ring opening
N杂环卡宾金络合物IPr ** AuNTf 2已被合成,光谱研究,结构表征并用作Hashmi苯酚合成中的高活性和稳定催化剂(IPr ** = 1,3- di - p - tolylimidazol带有两个二叔丁基苯甲基邻位的-2-亚烷基取代基,Tf =三氟甲磺酰基)。副反应包括不可逆的氧化芳烃开环,随后发生1,2,甲基转移。较高的阳离子金物质平衡浓度,对无活性双核中间体的规避和催化剂分解途径的抑制解释了辅助配体的空间需求的优势。炔烃的甲醇加成-水合反应具有烯基金催化剂静止状态的周转限制质子转移步骤,这由较大的主要动力学同位素效应和炔烃竞争实验所表明。