Triflic Acid Catalyzed Reductive Coupling Reactions of Carbonyl Compounds with O-, S-, and N-Nucleophiles
作者:Beate A. Gellert、Nils Kahlcke、Markus Feurer、Stefanie Roth
DOI:10.1002/chem.201101819
日期:2011.10.17
Highly efficient metal‐free reductivecoupling reactions of aldehydes and ketones with a range of nucleophiles in the presence of triflic acid (1–5 mol %) as the catalyst are presented. The reactions can be performed at ambient temperature without exclusion of moisture or air. A range of symmetrical and unsymmetrical ethers were obtained by this method in high yields and short reaction times. For the
Copper-Catalyzed Enantioselective Alkylation of Enolizable Ketimines with Organomagnesium Reagents
作者:Pablo Ortiz、Juan F. Collados、Ravindra P. Jumde、Edwin Otten、Syuzanna R. Harutyunyan
DOI:10.1002/anie.201609963
日期:2017.3.6
readily available organomagnesium reagents were used for the catalytic enantioselectivealkylation of enolizable N‐sulfonyl ketimines. The low reactivity and competing enolization of the ketimines was overcome by the use of a copper–phosphine chiral catalyst, which also rendered the transformation highly chemoselective and enantioselective for a broad range of ketimine substrates.
alkylation, and trifluoromethanesulfonic acid (triflic acid, TfOH) was also a good catalyst. The catalytic activity of metal triflates and TfOH increased in the order La(OTf)3 < Yb(OTf)3 < TfOH < Sc(OTf)3 < Hf(OTf)4. A mechanistic study was also performed. The reaction of 1-phenylethanol (4a) in the presence of Sc(OTf)3 in nitromethane gave an equilibrium mixture of 4a and bis(1-phenylethyl) ether (54). Addition
benzylamines has been achieved for the first time through transition-metal-catalyzed oxidative carbonylation, in which the new KR strategy offered a new approach to afford chiral isoindolinones (er up to 97 : 3) and the origin of chemoselectivity and stereoselectivity was confirmed by density functional theory (DFT) calculations.
Alkylation of Sulfonamides with Trichloroacetimidates under Thermal Conditions
作者:Daniel R. Wallach、John D. Chisholm
DOI:10.1021/acs.joc.6b01421
日期:2016.9.2
with trichloroacetimidates is reported. This transformation does not require an exogenous acid, base, or transition metal catalyst; instead the addition occurs in refluxing toluene without additives. The sulfonamide alkylation partner appears to be only limited by sterics, with unsubstituted sulfonamides providing better yields than more encumbered N-alkyl sulfonamides. The trichloroacetimidate alkylating