有机自由基通常是具有异常高反应性的短寿命中间体。从战略上讲,实现由有机自由基介导的合成有用的转化需要有效的引发和选择性终止事件。在这里,我们报告了一种新的催化策略,即双金属自由基氧化还原继电器,用于环氧化物向烯丙醇的区域和立体选择性重排。这种方法利用了 Ti 和 Co 配合物的丰富氧化还原化学,并将还原性环氧化物开环(引发)与氢原子转移(终止)相结合。至关重要的是,在影响关键的成键和断裂事件时,Ti 和 Co 催化剂彼此进行质子转移/电子转移以实现周转,从而构成真正协同的双催化系统。
有机自由基通常是具有异常高反应性的短寿命中间体。从战略上讲,实现由有机自由基介导的合成有用的转化需要有效的引发和选择性终止事件。在这里,我们报告了一种新的催化策略,即双金属自由基氧化还原继电器,用于环氧化物向烯丙醇的区域和立体选择性重排。这种方法利用了 Ti 和 Co 配合物的丰富氧化还原化学,并将还原性环氧化物开环(引发)与氢原子转移(终止)相结合。至关重要的是,在影响关键的成键和断裂事件时,Ti 和 Co 催化剂彼此进行质子转移/电子转移以实现周转,从而构成真正协同的双催化系统。
Catalytic Coupling of Carbon Dioxide with Terpene Scaffolds: Access to Challenging Bio-Based Organic Carbonates
作者:Giulia Fiorani、Moritz Stuck、Carmen Martín、Marta Martínez Belmonte、Eddy Martin、Eduardo C. Escudero-Adán、Arjan W. Kleij
DOI:10.1002/cssc.201600238
日期:2016.6.8
oxides and carbon dioxide into bio‐based cyclic organic carbonates catalyzed by Al(aminotriphenolate) complexes is reported. Both acyclic as well as cyclic terpene oxides were used as coupling partners, showing distinct reactivity/selectivity behavior. Whereas cyclic terpene oxides showed excellent chemoselectivity towards the organic carbonate product, acyclic substrates exhibited poorer selectivities
A phenylselenenyl chloride (PhSeCl)-mediated allylic oxidation to give allylicallyrearranged alcohol has been developed. A possible mechanism for the present reaction is generation of allylic selenide from prenyl moiety via [1,3]-sigmatropic rearrangement, followed by oxidation and [2,3]-sigmatropic rearrangement to afford 3-isopenten-2-ol.
Mixed disproportionation versus radical trapping in titanocene(III)-promoted epoxide openings
作者:José Justicia、Tania Jiménez、Sara P. Morcillo、Juan M. Cuerva、J. Enrique Oltra
DOI:10.1016/j.tet.2009.10.038
日期:2009.12
The formation of either deoxygenation products or allylic alcohols from epoxides is observed when these Substrates are treated with CP2TiCl under anhydrous conditions. It seems that processes via trisubstituted radicals give allylic alcohols whereas processes via disubstituted radicals may give deoxygenation products or allylic alcohols depending on the Structure of the original epoxide. This method allows a controlled access to these functional groups, providing a useful tool in organic synthesis. A mechanistic discussion for these transformations is reported. (c) 2009 Elsevier Ltd. All rights reserved.
Bimetallic Radical Redox-Relay Catalysis for the Isomerization of Epoxides to Allylic Alcohols
作者:Ke-Yin Ye、Terry MCallum、Song Lin
DOI:10.1021/jacs.9b04993
日期:2019.6.19
exceptionally high reactivity. Strategically, achieving synthetically useful transformations mediated by organic radicals requires both efficient initiation and selective termination events. Here, we report a new catalytic strategy, namely, bimetallic radical redox-relay, in the regio- and stereoselectiverearrangement of epoxides to allylic alcohols. This approach exploits the rich redox chemistry of Ti
有机自由基通常是具有异常高反应性的短寿命中间体。从战略上讲,实现由有机自由基介导的合成有用的转化需要有效的引发和选择性终止事件。在这里,我们报告了一种新的催化策略,即双金属自由基氧化还原继电器,用于环氧化物向烯丙醇的区域和立体选择性重排。这种方法利用了 Ti 和 Co 配合物的丰富氧化还原化学,并将还原性环氧化物开环(引发)与氢原子转移(终止)相结合。至关重要的是,在影响关键的成键和断裂事件时,Ti 和 Co 催化剂彼此进行质子转移/电子转移以实现周转,从而构成真正协同的双催化系统。