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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(4):1085-1089
Naphthalene and acenaphthene with peri 2‐py and BMes2 (py=pyridyl, Mes=mesityl) substituents have been found to undergo facile phototransformation, cleavage of a C−C bond of naphthalene, and formation of 2‐py‐bound benzoborepins as the major products. Mechanistic pathways of this photoreaction have been established by examination of both excited and ground states by using CASSCF and CASPT2 methods in DFT and time‐dependent DFT calculations. The mesityl to py‐naphthyl charge‐transfer transition and the mesityl migration from the boron atom to the naphthyl moiety drive this unprecedented C−C bond cleavage and boron‐insertion reaction. 相似文献
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Katsuaki Baba Mamoru Tobisu Naoto Chatani 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2013,125(45):11883-11883
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(7):1996-1999
The zirconium methylidene (PNP)Zr=CH2(OAr) ( 1 ) reacts with N3Ad to give two products (PNP)Zr=NAd(OAr) ( 2 ) and (PNP)Zr(η2‐N=NAd)(N=CH2)(OAr) ( 3 ), both resulting from a common cycloaddition intermediate (PNP)Zr(CH2N3Ad)(OAr) ( A ). Using a series of control experiments in combination with DFT calculations, it was found that 2 results from a nitrene by a carbene metathesis reaction in which N2 acts as a delivery vehicle and forms N2CH2 as a side product. In the case of 3 , N−N bond splitting of the azide at the α‐position allowed the isolation of a rare example of a parent ketimide complex of zirconium. Isotopic labeling studies and solid‐state X‐ray analysis are presented for 2 and 3 , in addition to an independent synthesis for the former. 相似文献
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Levy L. Cao Jiliang Zhou Zheng‐Wang Qu Douglas W. Stephan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(51):18658-18662
While (Ph2CN2)B(C6F5)3 is unstable, single electron transfer from Cp*2Co affords the isolation of stable products [Cp*2Co][Ph2CNNHB(C6F5)3] 1 and [Cp*Co(C5Me4CH2B(C6F5)3)] 2 . The analogous combination of Ph2CN2 and BPh3 showed no evidence of adduct formation and yet single electron transfer from Cp*2Cr affords the species [Cp*2Cr][PhC(C6H4)NNBPh3] 3 and [Cp*2Cr][Ph2CNNHBPh3] 4 . Computations showed both reactions proceed via transient radical anions of the diphenyldiazomethane–borane adducts to effect C?H bond activations. 相似文献
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Jianzhong Chen Zhenfeng Zhang Delong Liu Wanbin Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(29):8584-8587
A chemoselective C−O bond cleavage of the ester alkyl side‐chain of α‐acyloxy ketones was realized for the first time by a highly efficient palladium‐catalyzed hydrogenolysis (S/C=6000, the highest catalytic efficiency by far). Furthermore, a kinetic resolution of α‐acyloxy ketones was first developed by enantioselective hydrogenolysis with good yields and up to 99 % ee. 相似文献
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Jeroen Bomon Elias Van Den Broeck Mathias Bal Dr. Yuhe Liao Dr. Sergey Sergeyev Prof. Dr. Veronique Van Speybroeck Prof. Dr. Bert F. Sels Prof. Dr. Bert U. W. Maes 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(8):3087-3092
An efficient conversion of biorenewable ferulic acid into bio-catechol has been developed. The transformation comprises two consecutive defunctionalizations of the substrate, that is, C−O (demethylation) and C−C (de-2-carboxyvinylation) bond cleavage, occurring in one step. The process only requires heating of ferulic acid with HCl (or H2SO4) as catalyst in pressurized hot water (250 °C, 50 bar N2). The versatility is shown on a variety of other (biorenewable) substrates yielding up to 84 % di- (catechol, resorcinol, hydroquinone) and trihydroxybenzenes (pyrogallol, hydroxyquinol), in most cases just requiring simple extraction as work-up. 相似文献
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