Allylic Oxidations Catalyzed by Dirhodium Caprolactamate via Aqueous <i>tert</i>-Butyl Hydroperoxide: The Role of the <i>tert</i>-Butylperoxy Radical
作者:Emily C. McLaughlin、Hojae Choi、Kan Wang、Grace Chiou、Michael P. Doyle
DOI:10.1021/jo8021132
日期:2009.1.16
These oxidation reactions occur with aqueoustert-butylhydroperoxide (TBHP) without rapid hydrolysis of the caprolactamate ligands on dirhodium. Allylic oxidations of enones yield the corresponding enedione in moderate to high yields, and applications include allylic oxidations of steroidal enones. Although methylene oxidation to a ketone is more effective, methyl oxidation to a carboxylicacid can
Dirhodium (II) 己内酰胺在生成叔丁基过氧自由基方面表现出最佳效率,叔丁基过氧自由基是氢原子提取的选择性试剂。这些氧化反应发生在叔水溶液中-丁基氢过氧化物 (TBHP) 没有快速水解二铑上的己内酰胺配体。烯酮的烯丙基氧化以中等至高产率产生相应的烯二酮,其应用包括甾体烯酮的烯丙基氧化。虽然亚甲基氧化成酮更有效,但也可以实现甲基氧化成羧酸。在与其他金属催化剂的比较研究中描述了己内酰胺二铑 (II) 作为 TBHP 烯丙基氧化的催化剂的优越效率(催化剂的摩尔%,转化率)。不同的催化剂以相同的相对产率产生基本上相同的产物混合物表明催化剂不参与产物形成步骤。烯酮烯丙基氧化研究产生的机理影响为控制产物形成的因素提供了新的见解。以前未公开的歧化途径,由已发现混合过氧化物的叔丁氧基自由基,用于通过烯丙基氧化形成酮产物。
US8163944B2
申请人:——
公开号:US8163944B2
公开(公告)日:2012-04-24
Allylic Oxidations Catalyzed by Dirhodium Catalysts under Aqueous Conditions
申请人:Doyle Michael P.
公开号:US20090093638A1
公开(公告)日:2009-04-09
The present invention relates to compositions and methods for achieving the efficient allylic oxidation of organic molecules, especially olefins and steroids, under aqueous conditions. The invention concerns the use of dirhodium (II,II) “paddlewheel complexes, and in particular, dirhodium carboximate and tert-butyl hydroperoxide as catalysts for the reaction. The use of aqueous conditions is particularly advantageous in the allylic oxidation of 7-keto steroids, which could not be effectively oxidized using anhydrous methods, and in extending allylic oxidation to enamides and enol ethers.