pyrazoles was achieved by 1,3-dipolar cycloaddition of diazo compounds, generated in situ from N-tosylhydrazones, with unactivated bromovinyl acetals, which served as alkyne surrogates. The reaction tolerated N-tosylhydrazones bearing various substituted benzylidene groups, and a range of 3,5-disubstituted pyrazoles were obtained in yields of up to 92%.
Construction of α-Halogenated Boronic Esters via Visible Light-Induced C–H Bromination
作者:Feng-Chen Gao、Ming Li、Heng-Yu Gu、Xin-Yi Chen、Shuang Xu、Yi Wei、Kai Hong
DOI:10.1021/acs.joc.3c01915
日期:2023.10.6
α-Halogenated boronic esters are versatile building blocks that can be diversified into a wide variety of polyfunctionalized molecules. However, their synthetic potential has been hampered by limited preparation methods. Herein, we report a visible light-induced C–H brominationreaction of readily available benzyl boronic esters. This method features high yields, mild conditions, simple operation,
Rh(I)-Catalyzed Carbon-Carbon Double-Bond Formation by Coupling of (Quinolin-8-yl)methanone with Arylaldehyde Tosylhydrazone
作者:Jianhui Wang、Yexia Zhang、Jingjing Wang
DOI:10.1055/s-0033-1339316
日期:——
An alternative method for the direct arylvinylation of (quinolin-8-yl)methanone with substituted N'-benzylidene-4-methylbenzenesulfonohydrazide is described. The desired 3-aryl-1(quinolin-8-yl)prop-2-en-1-one products are obtained in high yields through the catalytic reaction of (quinolin-8-yl) methanone and N'-arylidene-4-methylbenzenesulfonohydrazide (2 equiv) with [Rh(PPh3)(3)Cl] (10 mol%), Ag2O (0.5 equiv), and Cs2CO3 (2 equiv) at 130 degrees C for 48 hours. Two plausible mechanisms involving C-H activation and migratory insertion of the carbene into the rhodium-carbon bond were proposed to explain the formation of the product.