This work demonstrates the use of hydroxyl amine-based amination reagents RSO2NH-OAc for the nondirected, Cu-catalyzed amination of benzylic C-H bonds. The amination reagents can be prepared on a gram scale, are benchtop stable, and provide benzylic C-H amination products with up to 86% yield. Mechanistic studies of the established reactivity with toluene as substrate reveal a ligand-promoted, Cu-catalyzed mechanism proceeding through Ph-CH2(NTsOAc) as a major intermediate. Stoichiometric reactivity of Ph-CH2(NTsOAc) to produce Ph-CH2-NHTs suggests a two-cycle, radical pathway for C-H amination, in which the decomposition of the employed diimine ligands plays an important role.
The thionophosphate–thiolophosphate † photoisomerization proceeds predominantly through a non-chain radical pathway. Synthetically viable benzylation of tetrahydrofuran, propan-2-ol and olefins ‡
作者:Veejendra K. Yadav、Rengarajan Balamurugan、Masood Parvez、Raghav Yamdagni
DOI:10.1039/b003501g
日期:——
The photoirradiation of thionophosphates, ROP(S)(OEt)2, derived from benzyl and vinylogously benzyl alcohols in CH3CN, with a Hanovia medium-pressure mercury lamp in a quartz vessel leads to the formation of the corresponding thiolophosphates, RSP(O)(OEt)2, through a non-chain radical pathway. This behavior of thionophosphates is unlike that of the related phosphates, which react through ionic dissociationârecombination processes. When the irradiation is conducted in solvents such as PriOH, THF and toluene, benzylation of these solvents takes place in synthetically respectable yields. Irradiation of thionophosphates in CH3CN leads to a convenient allylic benzylation of olefins.
The Nickel and Palladium Catalysed Stereoselective Cross Coupling of Cyclopropyl Nucleophiles with Aryl Halides
作者:R.-J. de Lang、L. Brandsma
DOI:10.1080/00397919808005715
日期:1998.1
Abstract The reaction of 2-phenylcyclopropylzinc chloride with some substituted (het)aryl halides gave the corresponding coupling products with good yields and stereoselectivities under the influence of a catalytic amount of Pd(PPh3)4. Other Ni-and Pd-catalysts were less efficient. Alkyl-substituted cyclopropyl nucleophiles gave lower yields.
摘要 在催化量的Pd(PPh3)4 作用下,2-苯基环丙基氯化锌与一些取代的(杂)芳基卤化物反应得到相应的偶联产物,具有良好的产率和立体选择性。其他 Ni 和 Pd 催化剂效率较低。烷基取代的环丙基亲核试剂的产率较低。
Selective C(sp3)–H isothiocyanation represents a significant strategy for the synthesis of isothiocyanate derivatives. We report herein an electrochemicalbenzylic isothiocyanation in a highly chemo- and site-selective manner under external oxidant-free conditions. The high chemoselectivity is attributed to the facile in situ isomerization of benzylic thiocyanates to isothiocyanates. Notably, the method
Iodine-Catalyzed Aminosulfonation of Hydrocarbons by Imidoiodinanes. a Synthetic and Mechanistic Investigation
作者:Angus A. Lamar、Kenneth M. Nicholas
DOI:10.1021/jo1015213
日期:2010.11.19
benzylic and some aliphatic saturated and unsaturatedhydrocarbons by reaction with imido-iodinanes (PhI═NSO2Ar) is catalyzed by I2 under operationally simple and mild conditions. The first examples of 1,2-functionalization of unactivated C−H bonds using imido-iodinanes as aminating agents are reported. Mechanistic investigations, including Hammett analysis, kinetic isotope effects, a cyclopropane clock experiment
Mechanistic study on benzylic oxidations catalyzed by bismuth(III) salts: X-ray structures of two bismuth–picolinate complexes
作者:Emmanuel Callens、Andrew J. Burton、Andrew J.P. White、Anthony G.M. Barrett
DOI:10.1016/j.tetlet.2008.04.044
日期:2008.6
We report studies that are consistent with benzylic oxidation reactions catalyzed using bismuth(III) salts proceeding via a radical mechanism. Additionally, X-ray structures of two potential bismuth-picolinate complex intermediates are reported. (C) 2008 Elsevier Ltd. All rights reserved.