transformation of alkynes by controlled manipulation of TsNBr2 mediated process. Alkynes could be readily converted to ketones and α-bromoketones via an oxybromination–debromination sequence. When alkynes are treated successively with TsNBr2, KI and Na2SO3 in a mixture of acetone and water at roomtemperature, corresponding ketones were obtained. On the other hand, treatment of alkynes with TsNBr2 and
通过控制TsNBr 2介导的过程,开发了炔烃的氧化转化的新方法。炔烃可以很容易地通过氧溴化-脱溴序列转化为酮和α-溴代酮。在室温下,在丙酮和水的混合物中依次用TsNBr 2,KI和Na 2 SO 3处理炔烃时,可获得相应的酮。另一方面,用TsNBr 2和Na 2 SO 3处理炔烃在室温下,在乙酸乙酯,丙酮和水的混合物中,可生成相应的α-溴代酮。还可以在室温下使用TsNBr 2在很短的时间内由相应的炔烃合成1-溴炔烃。在所有情况下,都可获得相应产品的优异收率。
Palladium-Catalyzed Sequential Nucleophilic Addition/Oxidative Annulation of Bromoalkynes with Benzoic Acids To Construct Functionalized Isocoumarins
for the preparation of 3-substituted isocoumarins via palladium-catalyzed nucleophilic addition/oxidative annulation of bromoalkynes with benzoic acids has been developed. Remarkably, preliminary mechanistic studies indicated that the transformation might proceed via a stereo- and regioselective nucleophilic addition and C–H functionalization procedure.
Regio- and Stereoselective Hydrophosphorylation of Ynamides for the Synthesis of β-Aminovinylphosphine Oxides
作者:Hai Huang、Hongjun Zhu、Jun Yong Kang
DOI:10.1021/acs.orglett.8b01065
日期:2018.5.4
A metal-free hydrophosphorylation of ynamides with diaryl phosphine oxides has been developed. A highly E-selective and β-regioselective hydrophosphorylation protocol has been established as a general method for the synthesis of diversely hydrophosphinylated products employing an in situ generated electrophilic phosphorus species. Deuterium incorporation experiments suggest that the amino phosphirenium
Lewis Acid Catalyzed Electrophilic Aminomethyloxygenative Cyclization of Alkynols with <i>N</i>,<i>O</i>-Aminals
作者:Anrong Chen、Houjian Yu、Jiaqi Yan、Hanmin Huang
DOI:10.1021/acs.orglett.9b04630
日期:2020.1.17
Lewis acid enables the electrophilic carbooxygenative cyclization of alkynols with N,O-aminals. The new process proceeds efficiently under very mild conditions via a pathway that is opposite to classical carbo-metalation. These reactions exhibit broad substrate generality and functional group compatibility, leading to a wide variety of 5-8-membered oxacycles bearing diverse functional groups. The cyclization