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
An efficient synthesis of diversely functionalized furans is developed via Cu-mediated intermolecular annulative couplings of acetylenic sulfones and activated methylenes, which provides a straightforward and atom-economic way to tetrasubstituted furan derivatives in good yields.
Photoinduced remote regioselective radical alkynylation of unactivated C–H bonds
作者:Qu-Ping Hu、Yu-Tao Liu、Yong-Ze Liu、Fei Pan
DOI:10.1039/d1cc06885g
日期:——
method for the remote regioselective alkynylation of unactivated C(sp3)–H bonds in diverse aliphatic amides by photogenerated amidyl radicals has been developed. The site-selectivity is dominated via a 1,5-hydrogenatomtransfer (HAT) process of the amide. Mild reaction conditions and high regioselectivity are demonstrated in this methodology.
We report here a regiospecific [3 + 2] annulation between aminocyclopropanes and various functionalized alkynes enabled by a P/N-heteroleptic Cu(I) photosensitizer under photoredox catalysis conditions. Thus, a divergent construction of 3-aminocyclopentene derivatives including methylsulfonyl-, arylsulfonyl-, chloro-, ester-, and trifluoromethyl-functionalized aminocyclopentenes could be achieved with
Gold‐Catalyzed Oxygen Transfer to Alkynylsulfones: A Diazo‐Free Route to 4‐Sulfonyl‐1,3‐Oxazoles
作者:Elena I. Chikunova、Dmitry V. Dar'in、Vadim Yu. Kukushkin、Alexey Yu. Dubovtsev
DOI:10.1002/adsc.202200751
日期:2022.11.8
The gold-catalyzed annulation of alkynylsulfones, involving pyridine N-oxides (as O-atom transfer reagents) and nitriles (as C=N synthons), comprises a diazo-free route to valuable 4-sulfonyl-1,3-oxazoles. This reaction operates under relatively mild conditions (IPrAuNTf2 5 mol %, rt or 60 °C), and a number of functionalities was compatible (35 examples; 14–95%). In most cases, the SO2 fragment, which
炔基砜的金催化环化,包括吡啶N-氧化物(作为O原子转移试剂)和腈(作为 C=N 合成子),包括生成有价值的 4-磺酰基-1,3-恶唑的无重氮途径。该反应在相对温和的条件下进行(IPrAuNTf 2 5 mol%,rt 或 60 °C),并且许多功能是兼容的(35 个示例;14-95%)。在大多数情况下,通常在先前报道的 Au 催化的O转移到炔基砜中排出的 SO 2片段保留在杂环产物中。假定的反应机制表明通过O原子转移形成的反应性金 α-氧代卡宾中间体的关键作用。