Nickel-Catalyzed Enantioselective α-Alkenylation of <i>N</i>-Sulfonyl Amines: Modular Access to Chiral α-Branched Amines
作者:Lun Li、Yu-Cheng Liu、Hang Shi
DOI:10.1021/jacs.1c00622
日期:2021.3.24
α-branched amines are common structural motifs in functional materials, pharmaceuticals, and chiral catalysts. Therefore, developing efficient methods for preparing compounds with these privileged scaffolds is an important endeavor in synthetic chemistry. Herein, we describe an atom-economical, modular method for a nickel-catalyzed enantioselective α-alkenylation of readily available linear N-sulfonyl amines
silyl alkynoate in N,N-dimethylformamide (DMF) at 80 °C in the presence of catalytic amounts of CuCl and PCy3 produced the corresponding alkynylsilane in excellent yield. The copper-catalyzed decarboxylation proceeded smoothly with low catalyst loadings (0.5 mol % of CuCl and 1.0 mol % of PCy3) under mild reaction conditions and is easily scalable to gram quantities.
Synthesis and reactions of donor cyclopropanes: efficient routes to cis - and trans -tetrahydrofurans
作者:Jonathan Dunn、Adrian P. Dobbs
DOI:10.1016/j.tet.2015.05.007
日期:2015.9
A detailed study on the synthesis and reactions of silylmethylcyclopropanes is reported. In their simplest form, these donor-only cyclopropanes undergo Lewis acid promoted reaction to give either cis- or trans-tetrahydrofurans, with the selectivity being reaction condition-dependant. The adducts themselves are demonstrated to be an important scaffold for structural diversification. The combination
On the Regioselectivity of the Nickel-Catalyzed Insertion of Alkynes into the Carbon–Carbon Bond of Oxetan-3-one
作者:Christophe Aïssa、Manuel Barday、Christopher Janot、Daniel Clare、Caitlin Carr-Knox、Bradley Higginson、Kelvin Ho
DOI:10.1055/s-0036-1589052
日期:2017.8
of unsymmetrical alkynes into the carbon–carbonbond of oxetan-3-one in the presence of a nickel catalyst has revealed a strong directing effect of a 2-thienyl substituent. This effect is larger than those of 2-vinylbenzene, trimethylsilyl, aryl, or 3-thienyl groups. The study of the regioselectivity of insertion of unsymmetrical alkynes into the carbon–carbonbond of oxetan-3-one in the presence of
Decatungstate as Direct Hydrogen Atom Transfer Photocatalyst for SOMOphilic Alkynylation
作者:Luca Capaldo、Davide Ravelli
DOI:10.1021/acs.orglett.1c00381
日期:2021.3.19
A versatile approach for the alkynylation of a variety of aliphatic hydrogen donors, including alkanes, is reported. We used tetrabutylammonium decatungstate as photocatalyst to generate organoradicals from C–H/Si–H bondsvia hydrogen atom transfer. The latter intermediates underwent SOMOphilic alkynylation by methanesulfonyl alkynes to afford internal alkynes upon loss of a sulfonyl radical. The effect