Transition-metal-free C–C bond cleavage and formation: efficient synthesis of 2,3-diarylimidazo[1,2-α]pyridines from 2-aminopyridines and alkynoates
作者:Zhengwang Chen、Yuelu Wen、Guotian Luo、Min Ye、Qinghao Wang
DOI:10.1039/c6ra19291b
日期:——
A highly efficient transition-metal-free cyclization reaction for the synthesis of 2,3-diarylimidazo[1,2-α]pyridines is described. A variety of substituted 2-aminopyridines and alkynoates are compatible under the standard conditions. This protocol is marked by the cleavage of a C–C bond and the formation of a new Csp2–Csp2 bond under transition-metal-free conditions.
Development of Gold-catalyzed [4+1] and [2+2+1]/[4+2] Annulations between Propiolate Derivatives and Isoxazoles
作者:Rajkumar Lalji Sahani、Rai-Shung Liu
DOI:10.1002/anie.201610665
日期:2017.1.19
new gold‐catalyzed annulations of isoxazoles with propiolates have been developed. Most isoxazoles follow an initial O attack on the alkyne to afford a [4+1] annulation product. This process results in a remarkable alkyne cleavage of initial propiolates. Unsubstituted isoxazoles proceed through an N attack step to yield formal [2+2+1]/[4+2] annulation products. These two annulation products arise initially
Gold-catalyzed formal [4π+2π]-cycloadditions of tert-butyl propiolates with aldehydes and ketones to form 4H-1,3-dioxine derivatives
作者:Somnath Narayan Karad、Wei-Kang Chung、Rai-Shung Liu
DOI:10.1039/c5cc04538j
日期:——
Novel gold-catalyzed [4π+2π]-cycloadditions of tert-butyl propiolates with aldehydes and ketones have been developed to form 4H-1,3-dioxine derivatives.
Selective synthesis of trisubstituted pyrroles through the reactions of alkynyl Fischer carbene complexes with oxazolones
作者:Julio López、Iván Velazco-Cabral、Eloy Rodríguez-deLeón、Clarisa Villegas Gómez、Francisco Delgado、Joaquín Tamariz、Ana Arrieta、Fernando P. Cossío、Miguel A. Vázquez
DOI:10.1039/c9ob02411e
日期:——
An efficient and simple synthesis of novel trisubstituted 1H-pyrroles 4a-qvia 1,3-dipolar cycloaddition of Δ3-trifluoromethyloxazolones 2a-d with both chromium and tungsten alkynyl Fischercarbenecomplexes (1a-h) is described. An unexpected and unreported -CF3 group elimination process was observed in the pyrrole structure. Our experimental and theoretical data suggested that the metal fragment may
A novel synthesis of oxazolidine-2,4-diones via an efficient fixation of CO<sub>2</sub>with 3-aryl-2-alkynamides
作者:Guofei Chen、Chunling Fu、Shengming Ma
DOI:10.1039/c0ob00550a
日期:——
A very mild protocol for fixation of carbon dioxide with 2-alkynamides in DMSO at 30 °C using a CO2 balloon in the presence of K2CO3 has been developed, which leads to an efficient assembly of oxazolidine-2,4-diones. It is observed that the regioselectivity was controlled by the aryl group.