A novel strategy for the crossdehydrogenativecoupling (CDC) of acetophenone hydrazones and aldehydes has been developed for the synthesis of highly substituted pyrazoles. This work, for the first time, uses elemental sulfur as a promoter as well as a hydrogen acceptor in effecting the Csp(3)-Csp(2) bond formation via C-H activation.
Enantioselective Synthesis of Trisubstituted Allenes via Cu(I)-Catalyzed Coupling of Diazoalkanes with Terminal Alkynes
作者:Wen-Dao Chu、Lei Zhang、Zhikun Zhang、Qi Zhou、Fanyang Mo、Yan Zhang、Jianbo Wang
DOI:10.1021/jacs.6b09674
日期:2016.11.9
A highly enantioselectivesynthesis of trisubstituted allenes has been achieved through Cu(I)-catalyzed cross-coupling of aryldiazoalkanes and terminal alkynes with chiral bisoxazoline ligands. Alkynyl migratory insertion of Cu(I) carbene is proposed as the key step for the construction of axialchirality.
Cu(I)-catalyzed coupling of diaryldiazomethanes with terminal alkynes: an efficient synthesis of tri-aryl-substituted allenes
作者:Chenggui Wu、Fangdong Hu、Zhenxing Liu、Guisheng Deng、Fei Ye、Yan Zhang、Jianbo Wang
DOI:10.1016/j.tet.2015.10.043
日期:2015.12
A highly efficient method for the synthesis of tri-aryl-substituted allenes has been developed through Cu(I)-catalyzed coupling of diaryldiazomethanes with terminalalkynes. The reaction is under mild conditions and uses simple and inexpensive CuI as the catalyst. Mechanistically, the reaction follows a pathway involving Cu(I) carbene migratory insertion.
Overcoming Scope Limitations in Cross-Coupling of Diazo Nucleophiles by Manipulating Catalyst Speciation and Using Flow Diazo Generation
作者:Ryan J. Sullivan、Garrett P. R. Freure、Stephen G. Newman
DOI:10.1021/acscatal.9b01180
日期:2019.6.7
palladium-catalyzed diazo cross-coupling reactions has been expanded to include arylchlorides by controlled diazo slow addition. The success of this strategy is based on manipulating speciation within the catalytic cycle through starvation of the diazo reagent to make the Pd(II) oxidative intermediate the resting state. The strategy is also applicable to cross-coupling reactions with arylbromides and, in combination
Olefination of aromatic ketones: synthesis of mono- and dihaloalkenes
作者:Vasily N. Korotchenko、Alexey V. Shastin、Valentine G. Nenajdenko、Elisabeth S. Balenkova
DOI:10.1039/b201131j
日期:2002.3.25
A new simple and efficient transformation of various aromatic ketones to the corresponding halo (dihalo) alkenes is described. The reaction proceeds under mild conditions to give the target products in good yields.