Results 21 to 30 of about 6,329 (228)

Three applications of path integrals: equilibrium and kinetic isotope effects, and the temperature dependence of the rate constant of the [1,5] sigmatropic hydrogen shift in (Z)-1,3-pentadiene [PDF]

, 2010
Recent experiments have confirmed the importance of nuclear quantum effects even in large biomolecules at physiological temperature. Here we describe how the path integral formalism can be used to describe rigorously the nuclear quantum effects on ...
A Calhoun, A Kohen, A Warshel, A Warshel, A Warshel, A Warshel, BJ Berne, C Predescu, DC Clary, DM Ceperley, H Liu, HB Schlegel, J Basran, J Merrick, J Vaníček, J Vaníček, J Vaníček, J Wang, JA Barker, Jiří Vaníček, JK Hwang, KM Doll, L Masgrau, M Ceotto, M Herman, M Parrinello, MHM Olsson, MJ Frisch, MJS Dewar, N Gresh, R Iftimie, SCL Kamerlin, T Yamamoto, T Zimmermann, Tomáš Zimmermann, WH Miller, WR Roth, WV Doering, Y Zhao, YT Chang   +39 more
core   +2 more sources

Enantioselective synthesis of (+)-petromyroxol, enabled by rhodium-catalyzed denitrogenation and rearrangement of a 1-sulfonyl-1,2,3-triazole [PDF]

, 2015
Petromyroxol is a non-racemic mixture of enantiomeric oxylipids isolated from water conditioned with larval sea lamprey. The (+)-antipode exhibits interesting biological properties but only 1 mg was isolated from >100000 L of water.
Boyer, Alistair
core   +2 more sources

Path integral evaluation of equilibrium isotope effects [PDF]

, 2009
A general and rigorous methodology to compute the quantum equilibrium isotope effect is described. Unlike standard approaches, ours does not assume separability of rotational and vibrational motions and does not make the harmonic approximation for ...
Angus W. R., Chandler D., Cowan R. D., Feynman R., Jiří Vaníček, Redlich O., Tomáš Zimmermann, Vaníček J.   +7 more
core   +2 more sources

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

Beilstein Journal of Organic Chemistry, 2023
For the first time, we elaborated a method for the synthesis of pyrimidines containing an allomaltol unit. The suggested approach is based on the reaction of 2-(1-(dimethylamino)-3-oxo-3-arylprop-1-en-2-yl)-3-hydroxy-6-methyl-4H-pyran-4-ones with ...
Constantine V. Milyutin, Andrey N. Komogortsev, Boris V. Lichitsky, Mikhail E. Minyaev, Valeriya G. Melekhina   +4 more
doaj   +1 more source

Total Synthesis of (+)‐Melonine and (+)‐N4‐Oxy Melonine Enabled by an Intramolecular Alkene Diamination Reaction

Angewandte Chemie, EarlyView.
A complexity‐generating intramolecular alkene diamination constitutes the pivotal step in the enantioselective synthesis of the title natural products featuring a strained, cage‐like pentacyclic architecture. Abstract Among more than four thousand monoterpene indole alkaloids (MIAs) isolated to date, only a few feature a 2,2,3‐trisubstituted indoline ...
Vincent Goëlo, Qian Wang, Jieping Zhu
wiley   +2 more sources

Reactive organoallyl species generated from aryl halides and allene: allylation of alpha,beta-unsaturated aldehydes and cyclic ketones employing Pd/In transmetallation processes [PDF]

, 2008
Allylation of α,β-unsaturated aldehydes and cyclic ketones promoted by Pd/In transmetallation processes has been studied. The unsaturated aldehydes underwent regioselective 1,2-addition to afford secondary homoally alcohols.
Anwar, Araki, Araki, Araki, Araki, Brase, Cacchi, Chan, Cleghorn, Cleghorn, Cooper, Cooper, Cooper, Denmark, Dupont, Fontana, Gai, Gomez, Grigg, Han, Hirashita, Hopkins, Howell, Kang, Kimura, Kless, Knodler, Larock, Laura A.T. Cleghorn, Law, Lee, Li, Littke, Liu, Marshall, Milena Simic, Miles, Miura, Miyabe, Nakahara, Norsikian, Ohno, Pardoe, Parrill, Podlech, Quan, Ronald Grigg, Sole, Tamaru, Tang, Tietze, Tsuji, Vladimir Savic, Wang, Zanoni, Zanoni, Zhou   +56 more
core   +2 more sources

Chiral terpene auxiliaries V: Synthesis of new chiral γ-hydroxyphosphine oxides derived from α-pinene

Beilstein Journal of Organic Chemistry, 2019
New chiral regioisomeric γ-hydroxyphosphine ligands were synthesized from α-pinene. The key transformation was the thermal [2,3]-sigmatropic rearrangement of allyldiphenylphosphinites, obtained from (1R,2R,4S,5R)-3-methyleneneoisoverbanol and (1R,2R,3R ...
Anna Kmieciak, Marek P. Krzemiński
doaj   +1 more source

Sigmatropic rearrangements in 5-allyloxytetrazoles [PDF]

, 2011
Mechanisms of thermal isomerization of allyl tetrazolyl ethers derived from the carbocyclic allylic alcohols cyclohex-2-enol and 3-methylcyclohex-2-enol and from the natural terpene alcohol nerol were investigated.
Abell, Abramovitch, Amin Ismael, Araújo, Araújo, Barkley, Basch, Becke, Bugalho, Bugalho, Cristiano, Cristiano, Cristiano, Cristiano, Daniela V. Coelho, Desarro, Dąbkowska, Frija, Frija, Frija, Frija, Frija, Frija, Frisch, Gu, Gómez-Zavaglia, Hashimoto, Head-Gordon, Igor Reva, Johnstone, Koldobskii, Lee, Luís M. T. Frija, M. Lurdes S. Cristiano, Mavromoustakos, McCarthy, Mishra, Pacios, Peng, Peng, Rui Fausto, Sandmann, Tamura, Toney   +43 more
core   +1 more source

Regio- and stereoselectivity in the Lewis acid- and NaH-induced reactions of thiocamphor with (R)-2-vinyloxirane [PDF]

, 2006
The reaction of the enolizable thioketone (1R,4R)-thiocamphor (=(1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptane-2-thione; 1) with (R)-2-vinyloxirane (2) in the presence of a Lewis acid such as SnCl4 or SiO2 in anhydrous CH2Cl2 gave the spirocyclic 1,3 ...
Fedorov, A, Fu, C, Heimgartner, H
core   +1 more source

A thermally-induced, tandem [3,3]-sigmatropic rearrangement/[2 + 2] cycloaddition approach to carbocyclic spirooxindoles

Beilstein Journal of Organic Chemistry, 2010
The synthesis of C3-carbocyclic spirooxindoles was realized by way of an intramolecular [2 + 2] cycloaddition reaction between a vinylidene indolin-2-one and an alkyne.
Kay M. Brummond, Joshua M. Osbourn
doaj   +1 more source