نتایج جستجو برای: regioselective synthesis

تعداد نتایج: 410958  

Journal: :Organic & biomolecular chemistry 2013
Cynthia M Hong Alexander V Statsyuk

A three-component reaction has been developed that allows the regioselective synthesis of thieno[2,3-c]pyrroles. The reaction is based on the ability of 2-acetyl-3-thiophenecarboxaldehyde to react with amine and thiol nucleophiles to produce the corresponding tri-substituted thieno[2,3-c]pyrroles, with water as the only by-product. The developed reaction expands the range of synthetically acces...

Journal: :Organic & biomolecular chemistry 2016
Puying Luo Qiuping Ding Yuanyuan Ping Jianan Hu

A mild and efficient tandem benzo[d]thiazole directed C-H iodination and trifluoromethylthiolation for the synthesis of ortho-trifluoromethylthiolated 2-arylbenzo[d]thiazoles have been developed using AgSCF3 as a coupling partner. The reaction exhibits a diverse array of functional group tolerance giving the desired products in good to excellent yields. Regioselective trifluoromethylthiolation ...

2016
Brett N Hemric Qiu Wang

This paper reports a novel approach for the direct and facile synthesis of 1,2-oxyamino moieties via an intermolecular copper-catalyzed oxyamination of olefins. This strategy utilizes O-benzoylhydroxylamines as an electrophilic amine source and carboxylic acids as a nucleophilic oxygen source to achieve a modular difunctionalization of olefins. The reaction proceeded in a regioselective manner ...

Journal: :The Journal of organic chemistry 2004
Guuske F Busscher Stan Groothuys René de Gelder Floris P J T Rutjes Floris L van Delft

A synthesis route toward 2-deoxystreptamine, a common structure in many of the clinically important aminoglycosides, is presented. Starting from p-benzoquinone and cyclopentadiene, 2-deoxystreptamine is synthesized with key steps involving Pd(0)-catalyzed rearrangement, a retro-Diels-Alder by flash vacuum thermolysis, and Yb(III)-directed regioselective epoxide opening. The obtained diazidocycl...

2013
Yury Minko Morgane Pasco Helena Chechik Ilan Marek

The carbocupration reactions of heterosubstituted alkynes allow the regio- and stereoselective formation of vinyl organometallic species. N-Alkynylamides (ynamides) are particularly useful substrates for the highly regioselective carbocupration reaction, as they lead to the stereodefined formation of vinylcopper species geminated to the amide moiety. The latter species are involved in numerous ...

2009
Rajesh Rengasamy Marcus J. Curtis-Long Hyung Won Ryu Kyeong Yeol Oh Ki Hun Park

(2S,3R)-3-Hydroxy-2-(hydroxymethyl)-3,6-dihydro-2H-pyridine 8, an important precursor for the synthesis of polyhydroxylated piperidine azasugars, has been prepared from L-serine. Highly stereoselective nucleophilic addition to amino aldehyde 5 gave the corresponding allylic alcohol 6 which proceeded to give dihydro-2H-piridine 7a via a Grubbs II catalyzed RCM. Stereoselective H-bond directed ep...

Journal: :Chemical communications 2015
Liang Zhang Mingzhu Zhao Xiaoming Zhao

A highly efficient one-pot approach for the synthesis of carbonyl 2-amino-pyrimidines from 1,3-diynes and guanidine in the presence of Cs2CO3 and DMSO has been described. In these reactions, 1,3-diynes act as a precursor of buta-1,2,3-trienes and guanidine serves as the N-C[double bond, length as m-dash]N source for the construction of pyrimidines. This methodology proves to be a tandem regiose...

Journal: :Chemical communications 2016
Jacob R Stepherson Frank R Fronczek Rendy Kartika

Herein we describe a new method, enabling the synthesis of highly functionalized 1,4-diketones that are readily differentiated as monosilylenol ethers under Brønsted acid catalysis. This synthetically useful chemistry exploited an intermediacy of unsymmetrical silyloxyallyl cations, which were directly captured by silyl enolates to create the targeted α,α carbon-carbon linkages in a regioselect...

2006
Andrey V. Samoshin Vyacheslav V. Samoshin

Solar photochemistry was proved to be efficient for the nucleophilic substitution of alkoxy groups by amines in alkoxynitrobenzenes. The results of the sun-induced photochemical substitution were comparable to the outcome of the same reaction under irradiation by a low-pressure mercury lamp. Using 4’-nitrobenzo-15-crown-5 as a starting material we obtained a polyether amino alcohol a precursor ...

Journal: :Accounts of chemical research 2000
A K Franz K A Woerpel

In this Account, we describe the development of stereospecific, stereoselective, regioselective, and chemoselective carbon-carbon bond-forming reactions of silacyclopropanes that occur under mild conditions. By appropriate choice of metal salt catalyst, the regiochemistry of these reactions may be tuned to give the desired product. Stereoselective nucleophilic substitution reactions and stereos...

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