Ratnasamy Somanathan

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Co-reporter:Felipe A. Servín, Domingo Madrigal, José A. Romero, Daniel Chávez, Gerardo Aguirre, Cecilia Anaya de Parrodi, Ratnasamy Somanathan
Tetrahedron Letters 2015 Volume 56(Issue 18) pp:2355-2358
Publication Date(Web):29 April 2015
DOI:10.1016/j.tetlet.2015.03.125
We report the synthesis of novel chiral wedge shaped C2-symmetric 1,3-benzenedisulfonamides as organocatalysts that hydrogen bond to the nitroolefins in the transition state of the Michael addition of carbonylic compounds, mimicking natural enzymes, leading to products in excellent yields (up to 99%) and enantioselectivities (up to 99%).
Co-reporter:José A. Romero, Angélica Navarrate, Felipe A. Servín, Domingo Madrigal, Andrew L. Cooksy, Gerardo Aguirre, Daniel Chávez, Ratnasamy Somanathan
Tetrahedron: Asymmetry 2014 Volume 25(13–14) pp:997-1001
Publication Date(Web):31 July 2014
DOI:10.1016/j.tetasy.2014.05.002
An oxygen–chlorine interaction is reported in the transition state of the Michael addition of acetone to nitrostyrene catalyzed by enantioenriched monosulfonamides. The interaction between the oxygen from the nitro group and the chlorine at the ortho-position of the sulfonamide moiety is supported by theoretical calculations. Asymmetric Michael addition products catalyzed by monosulfonamides were obtained in moderate yields and enantioselectivities.N-((1R,2R)-2-Aminocyclohexyl)-2,3-dichlorobenzenesulfonamideC12H16Cl2N2O2S[α]D20 = −20 (c 0.72, CH2Cl2)Absolute configuration: (1R,2R)Source of chirality: (R,R)-1,2-diaminocyclohexaneN-((1R,2R)-2-Aminocyclohexyl)-2,5-dichlorobenzenesulfonamideC12H16Cl2N2O2S[α]D20 = −29 (c 1.1, MeOH)Absolute configuration: (1R,2R)Source of chirality: (R,R)-1,2-diaminocyclohexaneN-((1R,2R)-2-Aminocyclohexyl)-2,6-dichlorobenzenesulfonamideC12H16Cl2N2O2S[α]D20 = −30 (c 0.84, CH2Cl2)Absolute configuration: (1R,2R)Source of chirality: (R,R)-1,2-diaminocyclohexaneN-((1R,2R)-2-aminocyclohexyl)-2,5-dibromobenzenesulfonamideC12H16Br2N2O2S[α]D20 = −17 (c 6.1, MeOH)Absolute configuration: (1R,2R)Source of chirality: (R,R)-1,2-diaminocyclohexane
Platensimycin,HPLC>95%
1,3-Benzenediol,2-[(1R,6R)-3-methyl-6-(1-methylethenyl)-2-cyclohexen-1-yl]-5-pentyl-
Methanaminium,N-[4-[[4-(dimethylamino)phenyl]phenylmethylene]-2,5-cyclohexadien-1-ylidene]-N-methyl-
delta-9-Tetrahydrocannabinol
Vancomycin
Morphinan-3,6-diol,7,8-didehydro-4,5-epoxy-17-methyl- (5a,6a)-, 3,6-diacetate
1H-Indol-4-ol,3-[2-(dimethylamino)ethyl]-
1(5H)-Phenazinone,5-methyl-
3-(2-Aminoethyl)-1H-indol-5-ol