isocyanates via base-induced β-elimination of haloform N-monosubstituted trihaloacetamides is described. The rate of reaction exhibits a strong dependence on the nature of the trihalomethyl group. Thus, while the reaction of tribromoacetamides proceeds at room temperature and the reaction of trichloroacetamides requires heating in polar solvents, no reaction could be observed for any of the corresponding
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
Nucleophilic Substitution Catalyzed by a Supramolecular Cavity Proceeds with Retention of Absolute Stereochemistry
作者:Chen Zhao、F. Dean Toste、Kenneth N. Raymond、Robert G. Bergman
DOI:10.1021/ja508799p
日期:2014.10.15
of reactions whose stereochemicalcourse is completely reversed are exceedingly rare. We report herein a class of water-soluble host assemblies that is capable of catalyzing the substitution reaction at a secondary benzylic carbon center to give products with overall stereochemical retention, while reaction of the same substrates in bulk solution gives products with stereochemical inversion. Such ability
作者:Nilamber A. Mate、Rowan I. L. Meador、Bhaskar D. Joshi、John D. Chisholm
DOI:10.1039/d2ob00127f
日期:——
N-Alkylation of isatins can be achieved utilizing trichloroacetimidate electrophiles and a Lewis acid catalyst. These reactions provide access to N-alkyl isatins, versatile scaffolds which are often employed in the synthesis of pharmaceutical lead structures as well as natural products. Secondary trichloroacetimidates that are precursors to stabilized carbocations provided excellent yields of the isatin