The Role of Aroyloxyl Radicals in the Formation of Solvent-derived Products in Photodecomposition of Diaroyl Peroxides. The Reactivity of Substituted Cyclohexadienyl Radicals and Intermediacy of ipso Intermediates
peroxide (TPO) in benzene and toluene afforded, among free-radical products, biphenyl and dimethylbiphenyls, respectively, which were solely derived from the aromatic solvents. The yields of biphenyls depended upon the rate with which the radical intermediates were generated from the peroxides in sufficiently high concentrations for their dimerization. Photolyses of TPO and dibenzoyl peroxide in 1,3
An efficient in situ prepared superacid BF3–H2O promoted benzylation of arenes using benzyl alcohols and acetates achieves various diarylalkanes.
一种高效的原位制备的超强酸BF3-H2O促进的芳烃苄基化反应,使用苄醇和醋酸酯制备各种二芳基烷烃。
Versatile and sustainable alcoholysis of amides by a reusable CeO<sub>2</sub> catalyst
作者:S. M. A. Hakim Siddiki、Abeda Sultana Touchy、Masazumi Tamura、Ken-ichi Shimizu
DOI:10.1039/c4ra07419j
日期:——
CeO2 was found to be a versatile and reusable heterogeneous catalyst for direct alcoholysis of primary amides to esters under neutral conditions, providing a sustainable, general, and economic synthetic method of esters.
The paper describes a cooperative NHC (N‐heterocyclic carbene) and ruthenium‐based redox catalysis for the mild aerobic oxidative esterification of various aromatic and heteroaromatic aldehydes. The ruthenium(II) complex Ru(bpz)3(PF6)2 (bpz=2,2′‐bipyrazine) as catalyst is shown to be compatible with free NHCs. The NHC is used in these cascade reactions for the umpolung of the aldehyde to form the corresponding
Efficient Transesterification/Acylation Reactions Mediated by <i>N</i>-Heterocyclic Carbene Catalysts
作者:Gabriela A. Grasa、Tatyana Güveli、Rohit Singh、Steven P. Nolan
DOI:10.1021/jo0267551
日期:2003.4.1
Imidazol-2-ylidenes, a family of N-heterocyclic carbenes (NHC), are efficient catalysts in the transesterification involving numerous esters and alcohols. Low catalyst loadings of aryl- or alkyl-substituted NHC catalysts mediate the acylation of alcohols with enol acetates in short reaction times at room temperature. Commercially available and more difficult to cleave methyl esters react with primary