نتایج جستجو برای: regioselectivity

تعداد نتایج: 1520  

Journal: :Chemical communications 2005
Gerhard Hilt Thomas Vogler Wilfried Hess Fabrizio Galbiati

The intermolecular cyclotrimerisation of terminal and internal alkynes can be catalysed by simple cobalt complexes such as a CoBr2(diimine) under mild reaction conditions when treated with zinc and zinc iodide with high regioselectivity in excellent yields.

Journal: :Chemical communications 2010
Shin Iwata Toshiyuki Hamura Keisuke Suzuki

Regioselective [2+2] cycloaddition of ynones or ynoates to siloxy(trialkoxy)ethene (KSA) is described. A siloxy group on the KSA directs the perfect regioselectivity, allowing rapid construction of various functionalized cyclobutenedione derivatives.

Journal: :Journal of the American Chemical Society 2015
Xiaomin Xie Shannon S Stahl

Cu/nitroxyl catalysts have been identified that promote highly efficient and selective aerobic oxidative lactonization of diols under mild reaction conditions using ambient air as the oxidant. The chemo- and regioselectivity of the reaction may be tuned by changing the identity of the nitroxyl cocatalyst. A Cu/ABNO catalyst system (ABNO = 9-azabicyclo[3.3.1]nonan-N-oxyl) shows excellent reactiv...

2017
Zheng-Hang Qi Yi Zhang Yun Gao Ye Zhang Xing-Wang Wang Yong Wang

The origin of the enantio- and regioselectivity of ring-opening reaction of oxabicyclic alkenes catalyzed by rhodium/Josiphos has been examined using M06-2X density functional theory(DFT). DFT calculations predict a 98% ee for the enantioselectivity and only the 1,2-trans product as one regio- and diastereomer, in excellent agreement with experimental results. The solvent tetrahydrofuran(THF) p...

2017
Harry J Shrives José A Fernández-Salas Christin Hedtke Alexander P Pulis David J Procter

Benzothiophenes are heterocyclic constituents of important molecules relevant to society, including those with the potential to meet modern medical challenges. The construction of molecules would be vastly more efficient if carbon-hydrogen bonds, found in all organic molecules, can be directly converted into carbon-carbon bonds. In the case of elaborating benzothiophenes, functionalization of c...

Journal: :Genome informatics. International Conference on Genome Informatics 2006
Kosuke Hashimoto Akiyasu C Yoshizawa Koichi Saito Takuji Yamada Minoru Kanehisa

Fatty acids are the major components of membrane molecules. The fact that unsaturated fatty acids play multiple important roles, physically and biologically, means that the ratio of unsaturated to saturated fatty acids in the membrane needs to be strictly regulated to maintain cellular homeostasis. The most ubiquitous and widespread modification to fatty acids, which results in a great diversit...

2017
Jennifer K. Matsui David N. Primer Gary A. Molander

A photoredox-catalyzed C–H functionalization of heteroarenes using a variety of primary, secondary, and tertiary alkyltrifluoroborates is reported. Using Fukuzumi's organophotocatalyst and a mild oxidant, conditions amenable for functionalizing complex heteroaromatics are described, providing a valuable tool for late-stage derivatization. The reported method addresses the three major limitation...

2008
Matthew Scheideman Guoqiang Wang Edwin Vedejs

Iodine activation induces intramolecular hydroboration of homoallylic and bis-homoallylic amine boranes with good to excellent control of regiochemistry compared to control experiments using excess THF*BH 3. Deuterium labeling and other evidence confirm that the iodine-induced hydroboration reaction of homoallylic amine boranes occurs via an intramolecular mechanism equivalent to the classical ...

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