Gold-Catalyzed Carbene Transfer to Alkynes: Access to 2,4-Disubstituted Furans
作者:Søren Kramer、Troels Skrydstrup
DOI:10.1002/anie.201200307
日期:2012.5.7
example of a gold‐catalyzed intermolecular addition of carbon ylides to terminal alkynes is reported (see scheme; DCE=dichloroethane, Tf=trifluoromethanesulfonyl). Subsequent intramolecular trapping of the generated gold carbene completes a formal [3+2] cycloaddition, which represents a novel synthesis of 2,4‐disubstituted furans.
A facile route toward 1,1-diarylethylenes 6 has been developed in good yields via mCPBA-promoted oxidation of β-hydroxysulfides 2, BF3·OEt2-mediated Friedel–Crafts reaction of the resulting β-hydroxysulfoxides 3 with oxygenated benzenes 4, followed by Pd/C-mediated [2,3]-sigmatropic rearrangement of sulfoxides 5. The protocol provides a short-term, easy-operational, inexpensive reagent, mild condition
Visible light mediated reductions of ethers, amines and sulfides
作者:Timothy M. Monos、Gabriel Magallanes、Leanne J. Sebren、Corey R.J. Stephenson
DOI:10.1016/j.jphotochem.2016.05.014
日期:2016.9
Visible light-mediated photoredox catalysis enables the chemoselective reduction of activated carbon–heteroatom bonds as a function of reduction potential. The expansion of the scope of C–X bond reductions towards less activated motifs, such as ethers, amines and sulfides, is important to both organic synthesis and macromolecular degradation method development. In the present report, exploration of
An Organocatalytic Regiospecific Synthesis of 1,5-Disubstituted 4-Thio-1,2,3-triazoles and 1,5-Disubstituted 1,2,3-Triazoles
作者:Dhevalapally B. Ramachary、Patoju M. Krishna、Jagjeet Gujral、G. Surendra Reddy
DOI:10.1002/chem.201503302
日期:2015.11.16
AbstractOrganocatalytic azide–ketone [3+2] cycloaddition (OrgAKC) of a variety of 1‐aryl‐2‐(arylthio)ethanones and 1‐alkyl‐2‐(alkylthio)ethanones with different aryl or alkyl azides is reported in dimethyl sulfoxide or solvent‐free under ambient conditions to furnish 1,5‐disubstituted 4‐thio‐1,2,3‐triazoles in a regiospecific manner, which are further converted into useful 1,5‐disubstituted 1,2,3‐triazoles by treatment with Raney Ni at 25 °C for 1–3 h. Notable features of the OrgAKC reaction include high rate and selectivity, solvent‐free conditions, easily available substrates and catalysts, a wide range of synthetic and medicinal applications, and excellent yields generating a vast library of triazoles.