A new protocol was developed to synthesize (enantioenriched) thioethers and selenoethersfrom (chiral) benzylic trimethylammonium salts and di(hetero)aryl disulfides or diselenides. These syntheses were promoted by the presence of weak base and did not require the use of any transition metal, and resulted in the target products with good to excellent yields (72–94%). Using quaternary ammonium salts
Ion Pair-Directed Regiocontrol in Transition-Metal Catalysis: A Meta-Selective C–H Borylation of Aromatic Quaternary Ammonium Salts
作者:Holly J. Davis、Madalina T. Mihai、Robert J. Phipps
DOI:10.1021/jacs.6b08164
日期:2016.10.5
interactions to direct transition-metal catalysis is a potentially powerful yet relatively underexplored strategy, with most investigations thus far focusing on using hydrogen bonds as the controlling element. We have developed an ion pair-directed approach to controlling regioselectivity in the iridium-catalyzed borylation of two classes of aromatic quaternaryammonium salts, leading to versatile meta-borylated
Cu2O-catalyzed C–S bond cross coupling of alkane-/arene-sulfinates and (enantioenriched) benzylic quaternaryammoniumsalts has been developed. The product benzylic sulfones were obtained in good to high yields (75–96%). Chiral arylmethyl sulfones with high enantiomeric excess (90–94% ee) were also synthesized in the presence of Cu2O and 1,1′-bis-(diphenylphosphino)ferrocene (dppf).
GO–Cu<sub>7</sub>S<sub>4</sub> catalyzed <i>ortho</i>-aminomethylation of phenol derivatives with <i>N</i>,<i>N</i>-dimethylbenzylamines: site-selective oxidative CDC
作者:Sonu Gupta、Nisha Chandna、Pooja Dubey、Ajai K. Singh、Nidhi Jain
DOI:10.1039/c8cc03396j
日期:——
supported on grapheneoxide (GO) have been synthesized for the first time from Cu2S, and used as highly efficient heterogeneous catalysts for oxidative ortho-selective C–H aminomethylation of phenols with N,N-dimethylbenzylamines. The NPs (30–80 nm) have been characterized by HRTEM, SEM-EDX, PXRD, FTIR, Raman, ICP-AES and XPS analyses. The NP catalyzed sp2–sp3 crossdehydrogenativecoupling (CDC) features
Putting CO2 to work: Carbondioxide is shown to be a general and selective methylating reagent for secondary and primary, aromatic and aliphatic amines under reductive conditions. A variety of tertiary amines are obtained from CO2 and commercially available silanes in high yields with good tolerance to nitrile, olefin, ether, ester, and hydroxy groups.