Stereoselective Synthesis of Trisubstituted Alkenes through Sequential Iron-Catalyzed Reductive<i>anti</i>-Carbozincation of Terminal Alkynes and Base-Metal-Catalyzed Negishi Cross-Coupling
作者:Chi Wai Cheung、Xile Hu
DOI:10.1002/chem.201504049
日期:2015.12.7
stereoselective synthesis of trisubstituted alkenes is challenging. Here, we show that an iron‐catalyzed anti‐selective carbozincation of terminal alkynes can be combined with a base‐metal‐catalyzed cross‐coupling to prepare trisubstituted alkenes in a one‐pot reaction and with high regio‐ and stereocontrol. Cu‐, Ni‐, and Co‐based catalytic systems are developed for the coupling of sp‐, sp2‐, and sp3‐hybridized
Intermolecular cyclotrimerization of haloketoalkynes and internal alkynes: facile access to arenes and phthalides
作者:A. P. Silvestri、J. S. Oakdale
DOI:10.1039/d0cc05706a
日期:——
arenes in a single step. The highest regioselectivities (96% single isomer) were observed when employing 2° and 3°-halopropiolamides. A mechanistic hypothesis accounting for this selectivity is proposed. Notably, by using 1,4-butynediol as the internal alkyne, in situ lactonization following [2+2+2]-cycloaddition generates therapeutically-relevant phthalide pharmacophores directly.
Metal-free synthesis of activated ynesulfonamides and tertiary enesulfonamides
作者:Lucile Andna、Laurence Miesch
DOI:10.1039/c9ob00947g
日期:——
An operationally simple synthesis of activated ynesulfonamides and enesulfonamides is described. Ynesulfonamides can be obtained through reaction of sulfonylamides with activated bromoalkynes and Triton B in a short time at room temperature. Likewise, terminal alkynes react with sulfonylamides to provide enesulfonamides. Z/E enesulfonamides can be transformed exclusively into E enesulfonamides.
Palladium-catalysed Hiyama Cross-coupling Reaction of Alkynyl Halides with Aryltrialkoxysilanes under Aerobic Conditions
作者:Jiansheng Tang、Cancheng Guo
DOI:10.3184/174751914x13897235400522
日期:2014.2
A palladium-catalysed Hiyama cross-couplingreaction of alkynyl halides with aryltrialkoxysilanes has been developed. Catalysed by bis(dibenzylideneacetone)palladium and in the presence of silver fluoride and potassium bicarbonate, a variety of alkynyl halides (I, Br and Cl), whether electron-deficient or electron-rich, underwent the cross-couplingreaction with aryltrialkoxysilanes at room temperature
Facile preparation of N-protected 2-alkylidene-1,3-imidazolidines
作者:Hiroyuki Naito、Takeshi Hata、Hirokazu Urabe
DOI:10.1016/j.tetlet.2008.02.006
日期:2008.3
Stereoselective preparation of unsymmetrically protected 2-alkylidene-1,3-imidazolidines was achieved by the reaction of N,N'-protected ethylenediamine, bromopropynamide, and K(3)PO(4) in hot DMF. When N-protected aminoethanol was used in place of the protected ethylenediamine, an oxazolidine derivative was produced. (C) 2008 Elsevier Ltd. All rights reserved.