Enantioselective Photochemical Carbene Insertion into C–C and C–H Bonds of 1,3-Diketones by a Guanidine-Amide Organocatalyst
作者:Shiyang Li、Cefei Zhang、Guihua Pan、Liangkun Yang、Zhishan Su、Xiaoming Feng、Xiaohua Liu
DOI:10.1021/acscatal.3c00192
日期:——
A visible-light-induced enantioselective free carbene transfer reaction of α-diazoesters with 1,3-diketones is established by utilizing a chiral bifunctional guanidine-amide organocatalyst. Selective insertion of free carbene into the C–C or C–Hbonds of 1,3-diketone could be achieved with α-diazoesters bearing different steric hindrances. The transformations enable the preparation of a series of 1
Synthesis, characterization, and crystal structures of new 3,5-diaryl-1H-pyrazoles
作者:Dun-Jia Wang、Chun-Yang Zheng、Ling Fan
DOI:10.1016/j.molstruc.2009.10.001
日期:2009.12
Seven new 3,5-diaryl-1H-pyrazoles were synthesized by the condensation of 1,3-diketones with hydrazine in ethanol, and characterized The crystal structures for 3(5)-(4-tert-butylphenyl)-5(3)-(4-fluorphenyl)-1H-pyrazole (5) and 3-(4-tert-butylphenyl)-5-(6-methoxy-naphthalen-2-yl)-1H-pyrazole (7) have been determined by X-ray crystal structure analysis. The N-H N intermolecular hydrogen bonds join the molecules into dimers. The NH proton of 5 is disordered, and its dimer is formed by the tautomers 5a5b or 5b5a Compound 7 only exists as a 7a tautomer, and its dimer consists of the tautomers 7a7a (C) 2009 Elsevier B V All rights reserved