P450-catalyzed regio- and stereoselective oxidative hydroxylation of disubstituted cyclohexanes: creation of three centers of chirality in a single CH-activation event
摘要:
Wild-type P450-BM3 is able to catalyze in a highly regio- and diastereoselective manner the oxidative hydroxylation of non-activated disubstituted cyclohexane derivatives lacking any functional groups, including cis- and trans-1,2-dimethylcyclohexane, cis- and trans-1,4-dimethylcyclohexane, and trans-1,4-methylisopropylcyclohexane. In all cases except chiral trans-1,2-dimethylcyclohexane as substrate, the single hydroxylation event at a methylene group induces desymmetrization with simultaneous creation of three centers of chirality. Certain mutants increase selectivity, setting the stage for future directed evolution work. (C) 2014 Elsevier Ltd. All rights reserved.
irradiation in the presence of catalytic amounts of [(DPEphos)(bcp)Cu]PF6 and an amine, a range of unactivated aryl and alkyl halides were shown to be smoothly activated through a rare Cu(I)/Cu(I)*/Cu(0) catalytic cycle. This complex efficiently catalyzes a series of radical processes, including reductions, cyclizations, and direct arylation of arenes.
Reduction of sulfonates and aromatic compounds with the NiCl2·2H2OLi-arene (cat.) combination
作者:Gabriel Radivoy、Francisco Alonso、Miguel Yus
DOI:10.1016/s0040-4020(99)00893-5
日期:1999.12
A series of alkyl mesylates, dimesylates and alkyl or aryl triflates have been reduced to the corresponding hydrocarbons with nickel(II) chloride dihydrate, an excess of lithium powder and a catalytic amount of DTBB (10 mol%) in THF at room temperature. This methodology applied to enol triflates allowed the preparation of olefins or alkanes depending on the amount of the Ni(II) salt used. The reduction
available catalysts based on inexpensive, environmentally benign base metals are therefore strongly needed. Furthermore, expanding the toolbox of methods based on photoredox catalysis will facilitate the discovery of new light-mediated transformations. This article details the use of a simple copper complex which, upon activation with blue light, can initiate a broad range of radicalreactions.
Heterogeneous Supramolecular Catalysis through Immobilization of Anionic M<sub>4</sub>L<sub>6</sub> Assemblies on Cationic Polymers
作者:Hiroyuki Miyamura、Robert G. Bergman、Kenneth N. Raymond、F. Dean Toste
DOI:10.1021/jacs.0c09556
日期:2020.11.11
selectivity and activity through specific host-guest interactions work under homogeneous conditions, enzymes in nature can operate under heterogeneous conditions as membrane-bound enzymes. In order to develop such a heterogeneous system, an immobilized chiral supramolecular cluster Ga416 (2) was introduced into cross-linked polymers with cationic functionalities. These heterogeneous supramolecular catalysts
Cob(I)alamin als Katalysator. 6. Mitteilung [1]. Bildung und Fragmentierung von Alkylcobalaminen, ein Gleichgewichtsprozess zwischen nukleophiler Addition und reduktiver Fragmentierung
作者:Albert Fischli、Peter Michael Müller
DOI:10.1002/hlca.19800630225
日期:1980.3.5
Cob(I)alamin as Catalyst. 6. Communication [1]. Formation and Fragmentation of Alkylcobalamins: the Nucleophilic Addition – Reductive Fragmentation Equilibrium