gem-difluorinated 2H-furans from reactions of BrCF2CO2Et with enaminones has been described. The reactions tolerate a wide variety of functional groups under metal-free conditions. An active aminocyclopropane is proposed to be a key intermediate through the cyclopropanation of difluorocarbene with enaminones, which further triggers a regioselective C–C bond cleavage in situ to afford the corresponding gem-difluorinated
已经描述了由 BrCF 2 CO 2 Et 与烯胺酮反应合成偕二氟化 2 H-呋喃的级联策略。该反应在无金属条件下耐受多种官能团。通过二氟卡宾与烯胺酮的环丙烷化反应,活性氨基环丙烷被认为是关键中间体,这进一步引发了区域选择性 C-C 键原位断裂,得到相应的偕二氟化2 H-呋喃。
Novel Synthesis of<i>N</i>-Phenyl-2-aminopyrimidine Derivatives under Solvent-Free Conditions
作者:Ivaylo Elenkov、Davor Kidemet、Vesna Prgomet
DOI:10.1055/s-2005-917074
日期:——
An efficient method for the solvent-free synthesis of N-phenyl-2-aminopyrimidines has been developed through cyclocondensation of N-phenylguanidine with enaminone in the presence of DBU. The procedure is experimentally simple with very short reaction times and good yields. According to this procedure a variety of N-phenyl-2-aminopyrimidines were synthesized.
An efficient and straightforward synthetic method for constructing trifluoromethyl 2H-thiophenes through [4 + 1] cycloaddition of enaminothiones with trifluoromethyl N-tosylhydrazones has been disclosed. The cycloaddition platforms were found to be compatible with a broad substrate scope and to show high regio- and stereo-selectivities under very mild reaction conditions such as room temperature, neutral
A straightforward strategy for synthesis of highly functionalized trifluoromethyl 2H-furans is described. The copper catalyzed method relies on a cascade cyclic reaction between enaminones and N-tosylhydrazones. This method allows the synthesis of 2-amino-3-trifluoromethyl-substituted 2H-furan derivatives carrying a quaternary stereogenic center as single diastereomers. The proposed reaction mechanism
Expedient Synthesis of gem-CF2-2H-Thiophenes from Enaminothiones
作者:Zhengyu Zhang、Yaojia Jiang、Xinyu Zhang、Xuheng Zhang、Rui Fu
DOI:10.1055/s-0043-1763749
日期:——
An expedient and easy-to-handle synthetic platform has been established for the constructing of 2H-thiophenes carrying fluorine atoms through [4+1] cyclization of enaminothiones with fluorinated carbene precursors. This simple reaction system is well compatible with a wide range of substrates under completely metal-free conditions. The resulting 2H-thiophenes can undergo further late-stage modifications