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James E. Thomson - One of the best experts on this subject based on the ideXlab platform.
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Solid state conformations of α,β-unsaturated hydroxamates derived from the ‘chiral Weinreb amide’ auxiliary (S)-N-1-(1′-naphthyl)Ethyl-O-tert-butylhydroxylamine
Tetrahedron-asymmetry, 2017Co-Authors: James A. Lee, Paul M. Roberts, James E. Thomson, Jingda YinAbstract:Abstract α,β-Unsaturated hydroxamates derived from the ‘chiral Weinreb amide’ auxiliary (S)-N-1-(1′-naphthyl)Ethyl-O-tert-butylhydroxylamine consistently adopt a defined conformation and undergo highly diastereoselective conjugate addition reactions with lithium amide reagents. The configuration of the N-1-(1′-naphthyl)Ethyl Group dictates the position of the O-tert-butyl Group and also the configuration adopted by the pyramidal nitrogen atom via a ‘chiral relay’ effect. Conjugate addition of lithium amide reagents to these substrates proceeds on the face opposite to both the O-tert-butyl Group and nitrogen lone-pair with high levels of diastereoselectivity.
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On the origins of diastereoselectivity in the alkylation of enolates derived from N-1-(1'-naphthyl)Ethyl-O-tert-butylhydroxamates: chiral Weinreb amide equivalents.
Journal of Organic Chemistry, 2010Co-Authors: Christopher J. Goodwin, David Hepworth, Paul M. Roberts, James E. ThomsonAbstract:The stereochemical outcome observed upon alkylation of enolates derived from N-1-(1′-naphthyl)Ethyl-O-tert-butylhydroxamates (chiral Weinreb amide equivalents) may be rationalized by a chiral relay mechanism. Deprotonation with KHMDS leads to a nonchelated (Z)-enolate in which the oxygen atoms adopt an anti-periplanar conformation. The configuration of the N-1-(1′-naphthyl)Ethyl Group dictates the conformation of the O-tert-butyl Group and the configuration adopted by the adjacent pyramidal nitrogen atom. Highly diastereoselective enolate alkylation then proceeds anti to both the bulky tert-butyl Group (sterically driven) and the N-lone pair (stereoelectronically driven).
Corey R Hopkins - One of the best experts on this subject based on the ideXlab platform.
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discovery of a series of 2 phenyl n 2 pyrrolidin 1 yl phenyl acetamides as novel molecular switches that modulate modes of kv7 2 kcnq2 channel pharmacology identification of s 2 phenyl n 2 pyrrolidin 1 yl phenyl butanamide ml252 as a potent brain penetrant kv7 2 channel inhibitor
Journal of Medicinal Chemistry, 2012Co-Authors: Yiu Yin Cheung, Beiyan Zou, Owen B Mcmanus, Craig W Lindsley, Corey R HopkinsAbstract:A potent and selective inhibitor of KCNQ2, (S)-5 (ML252, IC50 = 69 nM), was discovered after a high-throughput screen of the MLPCN library was performed. SAR studies revealed a small structural change (Ethyl Group to hydrogen) caused a functional shift from antagonist to agonist activity (37, EC50 = 170 nM), suggesting an interaction at a critical site for controlling gating of KCNQ2 channels.
Jieping Zhu - One of the best experts on this subject based on the ideXlab platform.
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sulfonamide and tertiary amine as nucleophiles in pd ii catalyzed diamination of alkynes synthesis of tetracyclic indolobenzothiazine s s dioxides
Organic Letters, 2015Co-Authors: Bo Yao, Qian Wang, Jieping ZhuAbstract:Pd(II)-catalyzed oxidative double cyclization of the 1,2-diarylethynes bearing an N-mEthyl-N-(2-methoxycarbonyl)Ethylamino and an aminosulfonyl Group afforded indolobenzothiazine S,S-dioxides in good to excellent yields. The 2-(methoxycarbonyl)Ethyl Group attached to the indolyl nitrogen is readily removed under basic conditions (DBU, DMF, 120 °C) to provide the corresponding tetracycles with a free indolyl nitrogen in excellent yields.
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2 methoxycarbonyl Ethyl as a removable n protecting Group synthesis of indoloisoquinolinones by pd ii catalyzed intramolecular diamination of alkynes
Organic Letters, 2015Co-Authors: Bo Yao, Qian Wang, Jieping ZhuAbstract:Pd(II)-catalyzed double cyclization of 1,2-diarylethynes bearing an N-mEthyl-N-[2-(methoxycarbonyl)Ethyl]amino and an aminocarbonyl Group at the ortho positions of the two aromatic rings afforded the tetracyclic N-[2-(methoxycarbonyl)Ethyl]indoloisoquinolinones in good to excellent yields. The N-[2-(methoxycarbonyl)Ethyl] Group is readily removed under basic conditions (DBU, DMF, 120 °C) to afford the corresponding tetracycles with a free indolyl nitrogen in excellent yields. The 2-(methoxycarbonyl)Ethyl as a removable N-protecting Group is illustrated in other Pd(II)- and Pd(0)-catalyzed and selenium-mediated transformations.
Paul M. Roberts - One of the best experts on this subject based on the ideXlab platform.
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Solid state conformations of α,β-unsaturated hydroxamates derived from the ‘chiral Weinreb amide’ auxiliary (S)-N-1-(1′-naphthyl)Ethyl-O-tert-butylhydroxylamine
Tetrahedron-asymmetry, 2017Co-Authors: James A. Lee, Paul M. Roberts, James E. Thomson, Jingda YinAbstract:Abstract α,β-Unsaturated hydroxamates derived from the ‘chiral Weinreb amide’ auxiliary (S)-N-1-(1′-naphthyl)Ethyl-O-tert-butylhydroxylamine consistently adopt a defined conformation and undergo highly diastereoselective conjugate addition reactions with lithium amide reagents. The configuration of the N-1-(1′-naphthyl)Ethyl Group dictates the position of the O-tert-butyl Group and also the configuration adopted by the pyramidal nitrogen atom via a ‘chiral relay’ effect. Conjugate addition of lithium amide reagents to these substrates proceeds on the face opposite to both the O-tert-butyl Group and nitrogen lone-pair with high levels of diastereoselectivity.
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On the origins of diastereoselectivity in the alkylation of enolates derived from N-1-(1'-naphthyl)Ethyl-O-tert-butylhydroxamates: chiral Weinreb amide equivalents.
Journal of Organic Chemistry, 2010Co-Authors: Christopher J. Goodwin, David Hepworth, Paul M. Roberts, James E. ThomsonAbstract:The stereochemical outcome observed upon alkylation of enolates derived from N-1-(1′-naphthyl)Ethyl-O-tert-butylhydroxamates (chiral Weinreb amide equivalents) may be rationalized by a chiral relay mechanism. Deprotonation with KHMDS leads to a nonchelated (Z)-enolate in which the oxygen atoms adopt an anti-periplanar conformation. The configuration of the N-1-(1′-naphthyl)Ethyl Group dictates the conformation of the O-tert-butyl Group and the configuration adopted by the adjacent pyramidal nitrogen atom. Highly diastereoselective enolate alkylation then proceeds anti to both the bulky tert-butyl Group (sterically driven) and the N-lone pair (stereoelectronically driven).
Jingda Yin - One of the best experts on this subject based on the ideXlab platform.
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Solid state conformations of α,β-unsaturated hydroxamates derived from the ‘chiral Weinreb amide’ auxiliary (S)-N-1-(1′-naphthyl)Ethyl-O-tert-butylhydroxylamine
Tetrahedron-asymmetry, 2017Co-Authors: James A. Lee, Paul M. Roberts, James E. Thomson, Jingda YinAbstract:Abstract α,β-Unsaturated hydroxamates derived from the ‘chiral Weinreb amide’ auxiliary (S)-N-1-(1′-naphthyl)Ethyl-O-tert-butylhydroxylamine consistently adopt a defined conformation and undergo highly diastereoselective conjugate addition reactions with lithium amide reagents. The configuration of the N-1-(1′-naphthyl)Ethyl Group dictates the position of the O-tert-butyl Group and also the configuration adopted by the pyramidal nitrogen atom via a ‘chiral relay’ effect. Conjugate addition of lithium amide reagents to these substrates proceeds on the face opposite to both the O-tert-butyl Group and nitrogen lone-pair with high levels of diastereoselectivity.