Avisible light photoredoxc atalytic method for the selective cleavage of single strong CÀFbond in trifluoromethyl ketones is reported. Single electron reduction of trifluoromethyl ketones generates difluoromethyl radicals which can be engaged in intermolecular C À Cb ond formation with Nmethyl-N-arylmethacrylamides to furnish fluorine-containing oxindole derivatives in good yields.T he reaction shows excellent chemoselectivity with good functional group tolerance under mild conditions.1 ,1,1,3,3,3-Hexafluoroisopropanol (HFIP) as as olvent plays ac ritical role for the selective single C À Fb ond cleavage.H igh-level DFT calculations are depicted to shed light on the mechanism.
Chiral analogues of squaramides have been fruitful in organocatalyzed asymmetric reactions over last decade. Alongside other H-bonding catalysts like ureas, thioureas: squaramides have been proved to be efficient asymmetric catalysts for the formation of acyclic and cyclic chiral molecules. A wide range of cyclic molecules bearing multiple functionalities and stereocenters have been synthesized by using several bifunctional squaramides as catalysts. These catalysts perform as base utilizing basic N atom in their chiral extension and help in stereoinduction by forming H-bonds with suitable H-bond acceptors. The present review focuses on assembling recent progresses of asymmetric synthesis of five and six membered rings promoted by squaramides. A handful of articles have been published by several research groups documenting asymmetric construction of five-and six-membered rings as part of interesting and complex molecular architectures. Different methodologies like conventional and formal cycloadditions or cascade reactions have been engineered through the assistance of chiral squaramides to fabricate the carbo-and heterocycles. This review also includes dual and cooperative catalytic system in which squaramide is one of the catalysts.
Olefin cross-metathesis is a cornerstone reaction in organic synthesis where stereoselectivity is typically governed by the structure of the catalyst. In this work, we show that merging Grubbs second generation...
A visible light photoredox catalytic method for the selective cleavage of single strong C−F bond in trifluoromethyl ketones is reported. Single electron reduction of trifluoromethyl ketones generates difluoromethyl radicals which can be engaged in intermolecular C−C bond formation with N‐methyl‐N‐arylmethacrylamides to furnish fluorine‐containing oxindole derivatives in good yields. The reaction shows excellent chemoselectivity with good functional group tolerance under mild conditions. 1,1,1,3,3,3‐Hexafluoroisopropanol (HFIP) as a solvent plays a critical role for the selective single C−F bond cleavage. High‐level DFT calculations are depicted to shed light on the mechanism.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.