Chemo- and regioselective synthesis of polysubstituted 2-aminothiophenes by the cyclization of<i>gem</i>-dibromo or<i>gem</i>-dichloroalkenes with β-keto tertiary thioamides
作者:Xuxue Zhang、Chuan Liu、Yupian Deng、Song Cao
DOI:10.1039/d0ob01821j
日期:——
A facile and practical method for the synthesis of 2,3,4-trisubstituted 2-aminothiophenes by the cyclization ofgem-dibromoalkenes orgem-dichloroalkenes with β-keto tertiary thioamides has been developed.
vinyl dichlorides and electron deficient amides as the starting material is described. In the absence of transition-metal catalyst, the reaction proceeds under mild reaction conditions in open air and thus rendering a convenient operation. This strategy is not only suitable for both terminal and internal ynamide synthesis but also amenable for large-scale preparation. Broad substrate scopes with respect
A convenient and straightforward strategy for the synthesis of 2,3-disubstituted and 2,3,5-trisubstituted furans via a base-promoted domino reaction of β-keto compounds with vinyl dichlorides is described. This transition-metal-free approach proceeds under operationally simple reaction conditions featuring easily available starting materials, a broad substrate scope, and good functional group tolerance
The first Pd/Cu catalyzed selective C2-alkenylation of pyridines with internal alkynes has been developed via the pyridinium salt activation strategy. Importantly, the configuration of the product alkenylpyridines could be tuned by the choice of the proper N-alkyl group of the pyridinium salts, thus allowing for both the Z- and E-alkenylpyridines synthesized with good regio- and stereoselectivity.
Efficient Multigram Approach to Acetylenes and CF
<sub>3</sub>
‐ynones Starting from Dichloroalkenes Prepared by Catalytic Olefination Reaction (COR)
作者:Vasiliy M. Muzalevskiy、Zoia A. Sizova、Arstan I. Diusenov、Alexey V. Shastin、Valentine G. Nenajdenko
DOI:10.1002/ejoc.202000531
日期:2020.7.23
Efficient two step approach towards terminal acetylenes was elaborated. At the first step, dichloroalkenes were prepared in up to 88 % yields by catalytic olefination reaction COR of arylaldehydes. Treatment of dichloroalkenes with n BuLi effectively led to the corresponding alkynes in up to 97 % yield. A versatile one pot procedure towards CF3‐ynones was elaborated to give these products in up to