N-Heterocyclic Carbene-Catalyzed [3 + 2] Annulation of 3,3'-Bisoxindoles with α-Bromoenals: Enantioselective Construction of Contiguous Quaternary Stereocenters.
Sign Up to like & getrecommendations! Published in 2022 at "Organic letters"
DOI: 10.1021/acs.orglett.2c02180
Abstract: An NHC-catalyzed enantio- and diastereoselective [3 + 2] annulation of α-bromoenals with bisoxindoles is developed, affording efficient access to various spirocyclic bisoxindole alkaloids. This protocol tolerates a broad substrates scope, with various spirocyclic bisoxindoles obtained… read more here.
Keywords: quaternary stereocenters; catalyzed annulation; annulation; annulation bisoxindoles ... See more keywords
Generation and [2,3]-Sigmatropic Rearrangement of Ammonium Ylides from Cyclopropyl Ketones for Chiral Indolizidines with Bridgehead Quaternary Stereocenters.
Sign Up to like & getrecommendations! Published in 2022 at "Organic letters"
DOI: 10.1021/acs.orglett.2c02759
Abstract: A sequence of nucleophilic ring opening of cyclopropyl ketones, N-quaternization, deprotonation, and [2,3]-sigmatropic rearrangement of ammonium ylides has been developed. This method enables efficient synthesis of bicyclic indolizidines bearing bridgehead aza-quaternary stereocenters from easily available… read more here.
Keywords: quaternary stereocenters; rearrangement ammonium; cyclopropyl ketones; ammonium ylides ... See more keywords
Stereoselective Electrophilic α-Alkynylation of α,α-Disubstituted N-tert-Butanesulfinyl Ketimines for Construction of Less Accessible Acyclic Quaternary Stereocenters.
Sign Up to like & getrecommendations! Published in 2022 at "Organic letters"
DOI: 10.1021/acs.orglett.2c03865
Abstract: In order to construct less accessible acyclic quaternary stereocenters, a protocol was developed to α-alkynylate α,α-disubstituted N-tert-butanesulfinyl ketimines stereoselectively using 1-(2-trimethylsilylethynyl)-1,2-benziodoxol-3(1H)-one in the presence of fluoride. Despite the steric and electrical similarity between the two… read more here.
Keywords: quaternary stereocenters; disubstituted tert; alkynylation; less accessible ... See more keywords
Fe-Catalyzed Alkylazidation of α-Trifluoromethylalkenes: An Access to Quaternary Stereocenters Containing CF3 and N3 Groups.
Sign Up to like & getrecommendations! Published in 2023 at "Organic letters"
DOI: 10.1021/acs.orglett.3c00439
Abstract: A concise Fe-catalyzed alkylazidation of α-trifluoromethylalkenes via a C-C bond cleavage/radical addition/azidation cascade is described. This protocol features a broad substrate scope, excellent functional group compatibility, and the ability to be performed on a gram… read more here.
Keywords: quaternary stereocenters; trifluoromethylalkenes access; catalyzed alkylazidation; alkylazidation trifluoromethylalkenes ... See more keywords
Asymmetric para-Functionalization of Anilines Via Chiral Phosphoric Acid Catalysis: Access to CF3-Substituted Indole-Aniline Quaternary Stereocenters.
Sign Up to like & getrecommendations! Published in 2025 at "Organic letters"
DOI: 10.1021/acs.orglett.5c04100
Abstract: We report a chiral phosphoric acid-mediated para-selective functionalization of diphenylamines with propargylic 3-methyleneindoles, enabling the construction of acyclic quaternary stereocenters bearing a trifluoromethyl substituent under mild conditions. This protocol delivers indole-aniline frameworks in good yields… read more here.
Keywords: indole aniline; asymmetric para; chiral phosphoric; quaternary stereocenters ... See more keywords
Tuning the Reactivity of Ketones through Unsaturation: Construction of Cyclic and Acyclic Quaternary Stereocenters via Zn-ProPhenol Catalyzed Mannich Reactions
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DOI: 10.1021/acscatal.8b04685
Abstract: Introduction of unsaturation adjacent to the carbonyl drastically improves the reactivity of the Zn-ProPhenol catalyzed Mannich reactions between N-carbamoyl imines and a-branched ketones. Despite only a small change in the substrate acidity, the bimetallic catalyst… read more here.
Keywords: cyclic acyclic; acyclic quaternary; catalyzed mannich; quaternary stereocenters ... See more keywords
Enantioselective Construction of Quaternary Stereocenters via A Chiral Spiro Phosphoric Acid-Assisted Formal Gold Carbene gem-Dialkylation Reaction.
Sign Up to like & getrecommendations! Published in 2024 at "Journal of the American Chemical Society"
DOI: 10.1021/jacs.4c04540
Abstract: Enantioselective construction of all-carbon quaternary stereocenters has attracted much attention over the past few decades. A variety of catalytic asymmetric methods have been disclosed based on the use of presynthesized complex reagents that impart congested… read more here.
Keywords: reaction; quaternary stereocenters; enantioselective construction; gold ... See more keywords
Organo-Cation Catalyzed Asymmetric Homo/Heterodialkylation of Bisoxindoles: Construction of Vicinal All-Carbon Quaternary Stereocenters and Total Synthesis of (-)-Chimonanthidine.
Sign Up to like & getrecommendations! Published in 2018 at "Journal of the American Chemical Society"
DOI: 10.1021/jacs.8b05386
Abstract: A novel chiral spirocyclic amide (SPA)-derived triazolium organocatalyst has been designed and demonstrated to effect asymmetric homo- and heterodialkylations of various bisoxindoles, enabling enantioselective construction of vicinal all-carbon quaternary stereocenters. These reactions feature excellent enantio-… read more here.
Keywords: carbon quaternary; quaternary stereocenters; vicinal carbon; total synthesis ... See more keywords
Construction of All-Carbon Quaternary Stereocenters by Scandium-Catalyzed Intramolecular C-H Alkylation of Imidazoles with 1,1-Disubstituted Alkenes.
Sign Up to like & getrecommendations! Published in 2020 at "Journal of the American Chemical Society"
DOI: 10.1021/jacs.9b12503
Abstract: The exo-selective C-H cycloaddition of imidazoles to 1,1-disubstituted alkenes has been achieved for the first time by using half-sandwich scandium catalysts. A wide range of imidazole compounds bearing various 1,1-disubstituted aliphatic alkenes, styrenes, dienes and… read more here.
Keywords: construction carbon; carbon quaternary; quaternary stereocenters; imidazoles disubstituted ... See more keywords
An enantioselective cascade for simultaneous generation of five quaternary stereocenters from fully substituted enones.
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DOI: 10.1039/c7cc03995f
Abstract: A highly enantioselective cascade reaction for the generation of five quaternary stereocenters in one-pot operation is reported for the first time in the history of organic synthesis. Cinchona-alkaloid derived hydrogen-bonding catalyst furnished structurally complex cascade… read more here.
Keywords: quaternary stereocenters; five quaternary; cascade simultaneous; generation five ... See more keywords
Cross-dehydrogenative coupling enables enantioselective access to CF3-substituted all-carbon quaternary stereocenters†
Sign Up to like & getrecommendations! Published in 2020 at "Chemical Science"
DOI: 10.1039/c9sc05894j
Abstract: A cross-dehydrogenative coupling strategy for enantioselective access to acyclic CF3-substituted all-carbon quaternary stereocenters has been established. By using catalytic DDQ with MnO2 as an inexpensive terminal oxidant, asymmetric cross coupling of racemic δ-CF3-substituted phenols with… read more here.
Keywords: quaternary stereocenters; cf3 substituted; cross dehydrogenative; carbon quaternary ... See more keywords