Search results for "SELE"
showing 10 items of 4721 documents
ChemInform Abstract: Synthesis and Stereochemical Studies of 2-Substituted Thiazolidine-4-carboxamide Derivatives.
2010
A series of new 2-substituted thiazolidine-4-carboxamide derivatives which have potentially useful immunological properties, have been synthesized in a stereoselective manner by coupling 2-subsituted thiazolidine-4-carboxylic acids with amines or amino esters. The structure of these compounds was established by combination of NMR methods and by X-ray analysis.
ChemInform Abstract: Rhodium(III)-Catalyzed Ring-Opening of Strained Olefins Through C-H Activation of O-Acetyl Ketoximes: An Efficient Synthesis of …
2014
An efficient strategy for the stereoselective synthesis of functionalized cyclopentenes and spiro[2.4]heptenes from strained olefins via C–H activation of aryl ketone O-acetyl ketoximes using [RhCl2Cp∗]2 catalyst is described. The results revealed that a wide range of readily accessible aryl and heteroaryl ketoximes are compatible in this method for the ring opening of bicyclic and spirotricyclic olefins.
Ab Initio Study of Stereo- and Regioselectivity in the Diels−Alder Reaction between 2-Phenylcyclopentadiene and α-(Methylthio)acrylonitrile
1997
Ab initio molecular orbital calculations have been used to investigate the Diels−Alder reaction between 2-phenylcyclopentadiene and α-(methylthio)acrylonitrile. Geometry optimizations were performed with the RHF/3-21G, RHF/3-21G*, and RHF/6-31G* calculations while the correlation energy has been calculated at MP2 and MP3 levels. Four asynchronous transition structures corresponding to the formation of different stereoisomers and regioisomers associated with the four reaction channels have been located. The observed endo/exo stereoselectivity and para/meta regioselectivity are correctly described at all levels of calculation, and the calculated activation energies reflect accurately the rela…
ChemInform Abstract: Iodine-Induced Stereoselective Carbocyclizations - A New Method for the Synthesis of Cyclohexane and Cyclohexene Derivatives.
1989
Photochemical Nitration by Tetranitromethane. Part XL. Regiochemistry of Trinitromethyl Attachment in the Photolysis of Benzofuran with Tetranitromet…
1997
(3RS,1SR)-3-Bromo-3-(1-phenylpropyl)chroman-2,4-dione
2005
The title compound, C18H15BrO3, was obtained by bromination of phenprocoumone with N-bromosuccinimide. The X-ray structure confirms an earlier proposal concerning the regioselectivity of the reaction to introduce the Br atom at the 3-position.
ChemInform Abstract: Unique Regioselectivity in the C(sp3)-H α-Alkylation of Amines: The Benzoxazole Moiety as a Removable Directing Group.
2015
The benzoxazol-2-yl substituent is easily introduced by oxidative coupling or nucleophilic substitution and can be removed by hydroxide or by hydride reduction.
Enantioselective Synthesis of 2-Isoxazolines by a One-Flask Conjugate Addition/Oxime-Transfer Process
2009
Enantioselective isoxazoline synthesis: A combination of 1) a catalytic enantioselective conjugate addition of oximes to alpha,beta-unsaturated aldehydes and 2) an acid-catalyzed intramolecular oxime-transfer reaction lead to the first asymmetric synthesis of 3-unsubstituted 2-isoxazolines (see scheme).
ChemInform Abstract: Enantioselective Synthesis of 2-Isoxazolines by a One-Flask Conjugate Addition/Oxime-Transfer Process.
2009
Enantioselective isoxazoline synthesis: A combination of 1) a catalytic enantioselective conjugate addition of oximes to alpha,beta-unsaturated aldehydes and 2) an acid-catalyzed intramolecular oxime-transfer reaction lead to the first asymmetric synthesis of 3-unsubstituted 2-isoxazolines (see scheme).
Enantioselective LaIII-pyBOX-Catalyzed Nitro-Michael Addition to (E)-2-Azachalcones
2013
A [La(OTf)3] complex with a new pyBOX ligand bearing a bulky 1-naphthylmethyl substituent at the 4′-position of the oxazoline ring catalyzes the conjugate addition of nitroalkanes to a broad range of (E)-2-azachalcones, providing the expected nitro-Michael products with good yields and enantiomeric excesses up to 87 %. The optical purity of the products can be increased by a single crystallization. A plausible stereochemical model to account for the observed stereochemistry has been proposed.