Oligosubstituted Pyrroles Directly from Substituted Methyl Isocyanides and Acetylenes
作者:Alexander V. Lygin、Oleg V. Larionov、Vadim S. Korotkov、Armin de Meijere
DOI:10.1002/chem.200801395
日期:2009.1
methyl isocyanides 1 onto the triple bond of electron‐deficient acetylenes 2 represents a direct and convenient approach to oligosubstituted pyrroles 3. The scope and limitations of this reaction (24 examples, 25–97 % yield) are reported along with an optimization of the reaction conditions and a rationalization of the mechanism. In addition, a related newly developed CuI‐mediated synthesis of 2,3‐disubstituted
Functionalizedindolizines were prepared by Lewis acid‐catalyzed cyclizations of 3‐(pyridin‐2‐yl)‐propiolates with enones. This new type of reaction provides a convenient and regioselective approach to ester‐substituted indolizine derivatives which are not readily available by other methods. Based on density function theory (DFT) calculations, a mechanism of the reaction has been suggested.
We report the phosphine-catalyzed intermolecular carbofluorination of alkynes using acyl fluorides as fluorinating reagents. This reaction promises to be a useful method for the synthesis of highly substituted monofluoroalkene derivatives since acyl fluorides can be easily prepared from the corresponding carboxylic acid derivatives and the reaction proceeds under ambient conditions without the need
CsF-promoted carboxylation of aryl(hetaryl) terminal alkynes with atmospheric CO<sub>2</sub> at room temperature
作者:B. Yu、P. Yang、X. Gao、Z. Z. Yang、Y. F. Zhao、H. Y. Zhang、Z. M. Liu
DOI:10.1039/c7nj01779k
日期:——
A CsF-promoted carboxylation of aryl(hetaryl) terminal alkynes with atmospheric CO2 in the presence of trimethylsilylacetylene was developed to give functionalized propiolic acid products at roomtemperature. A wide range of propiolic acids bearing functional groups was successfully obtained in good to excellent yields. Mechanistic studies demonstrate that in the carboxylation process the alkynylsilane
entry to the corresponding β-silylenamides and -acrylates, which were formed with high levels of regio- and stereoselectivities. A highly efficient catalytic silylcupration of activated alkynes is reported. Upon reaction with silylboronates and methanol in THF at room temperature in the presence of copper(I) fluoride tris(triphenylphosphine), a range of ynamides and propiolates were found to undergo a