نتایج جستجو برای: couplings reaction

تعداد نتایج: 428859  

Journal: :The Journal of chemical physics 2010
Zhigang Sun Dong H Zhang Millard H Alexander

We describe a time-dependent wavepacket based method for the calculation of the state-to-state cross sections for the Cl+H(2) reaction including all couplings arising from the nonzero spin and electronic orbital angular momenta of the Cl atom. Reactant-product decoupling allows us to use a physically correct basis in both the reactant and the product arrangements. Our calculated results agree w...

Journal: :Journal of the American Chemical Society 2008
David A Evans Lisbet Kvaernø Travis B Dunn André Beauchemin Brian Raymer Jason A Mulder Edward J Olhava Martin Juhl Katsuji Kagechika David A Favor

The synthesis of the marine neurotoxin azaspiracid-1 has been accomplished. The individual fragments were synthesized by catalytic enantioselective processes: A hetero-Diels-Alder reaction to afford the E- and HI-ring fragments, a carbonyl-ene reaction to furnish the CD-ring fragment, and a Mukaiyama aldol reaction to deliver the FG-ring fragment. The subsequent fragment couplings were accompli...

Journal: :Organic & biomolecular chemistry 2015
Peng Zhao Marshall D Young Christopher M Beaudry

The regiochemical outcome of Suzuki couplings of non-symmetric dibromobenzenes is investigated. Selectivities are dependent on the proximity of the bromine atom to alkene substituents, not on steric or electronic effects. Extension to a one-pot three-component Suzuki reaction leads to efficient terphenyl syntheses.

Journal: :Angewandte Chemie 2015
Surendra Thapa Arjun Kafle Santosh K Gurung Adam Montoya Patrick Riedel Ramesh Giri

Reported herein is an unprecedented ligand-free copper-catalyzed cross-coupling of alkyl-, aryl-, and alkynylzinc reagents with heteroaryl iodides. The reaction proceeds at room temperature for the coupling of primary, secondary, and tertiary alkylzinc reagents with heteroaryl iodides without rearrangement. An elevated temperature (100 °C) is required for aryl-heteroaryl and alkynyl-heteroaryl ...

Journal: :Chemical communications 2012
Guo-ping Lu Karl R Voigtritter Chun Cai Bruce H Lipshutz

Unexpected losses in stereochemistry from Stille reactions involving Z-alkenyl halides have been shown to be ligand dependent. A new set of reaction conditions has been developed that, in most cases, leads to highly stereoselective cross-couplings under mild conditions, along with improved yields.

Journal: :Organic letters 2004
Stanislaw F Wnuk Pedro I Garcia Zhizhong Wang

[reaction: see text] Radical-mediated silyl- and germyldesulfonylations of various vinyl and (alpha-fluoro)vinyl sulfones with tris(trimethylsilyl)silane and germanium hydrides provide access to vinyl and (alpha-fluoro)vinyl silanes and germanes. Upon oxidative treatment with hydrogen peroxide in basic aqueous solution, the vinyl tris(trimethylsilyl)silanes and -germanes undergo Pd-catalyzed cr...

Journal: :Organic letters 2006
Bruce H Lipshutz David W Chung Brian Rich Ricardo Corral

Di-p-chlorobenzyl azodicarboxylate (DCAD) is introduced as a novel, stable, solid alternative to DEAD and DIAD for a variety of Mitsunobu couplings. DCAD/Ph(3)P-mediated reactions in CH(2)Cl(2) generate a readily separable hydrazine byproduct. [reaction: see text]

Journal: :Angewandte Chemie 2015
Chuanhu Lei Xiaojia Jin Jianrong Steve Zhou

Three-component couplings were achieved from common aryl halides, alkyl halides, and heteroarenes under palladium and norbornene co-catalysis. The reaction forges hindered aryl-heteroaryl bonds and introduces ortho-alkyl groups to aryl rings. Various heterocycles such as oxazoles, thiazoles and thiophenes underwent efficient coupling. The heteroarenes were deprotonated in situ by bases without ...

Journal: :Organic & biomolecular chemistry 2011
Martín J Riveira Chakicherla Gayathri Armando Navarro-Vázquez Nicolay V Tsarevsky Roberto R Gil Mirta P Mischne

A new approach to the synthesis of cyclopenta[b]benzofuran derivatives via reaction of 1,3-dicarbonyl compounds with α,β,γ,δ-unsaturated aldehydes is described. The constitution and configuration of the new products have been firmly established by means of residual dipolar couplings (RDCs) and ab initio (13)C NMR chemical shift predictions.

1993
M. L. STONG

We study possible deviations from the Standard Model in the reaction e + e − → Zφ, where φ denotes a spinless neutral boson. We show how the Z decay angular correlation can be used to extract detailed information on the φ couplings, such as the parity of φ, radiatively induced form factor effects and possible CP violation in the scalar sector.

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