نتایج جستجو برای: regioselective synthesis

تعداد نتایج: 410958  

Journal: :Chemical communications 2005
Gerhard Hilt Patrick Bolze Iris Kieltsch

An intermolecular ring expansion reaction of an aryl epoxide with several dienes, acrylates, enynes or styrenes under iron catalysis, generated tetrahydrofuran derivatives in a highly chemo- and regioselective fashion. The process could be used in an unprecedented way for the one step synthesis of racemic calyxolane A and calyxolane B with acceptable diastereoselectivity.

2014
Navendu Jana Quyen Nguyen Tom G. Driver

The scope and limitations of a Suzuki reaction between 2-azidoarylboronic acid pinacolate esters and vinyl triflates are reported. This cross-coupling reaction enables the regioselective synthesis of indoles after a subsequent Rh(II)2-catalyzed sp(2)-C-H bond amination reaction.

Journal: :Organic & biomolecular chemistry 2013
Yan Yang Meng Gao Wen-Ming Shu Liu-Ming Wu Dong-Xue Zhang An-Xin Wu

A highly efficient method for the direct synthesis of α-iodoketals from methyl ketones has been developed via sustainable integration of orthogonal tandem catalytic reactions: copper(II) oxide catalyzed iodination reaction and the subsequent excess or regenerated iodine catalyzed regioselective ketalization reaction.

Journal: :Organic letters 2000
M T Crimmins C A Carroll B W King

[reaction: see text] The synthesis of the C1-C13 fragment 3 of leucascandrolide A has been completed utilizing a stereoselective and regioselective reductive cleavage of a highly functionalized spiroketal to incorporate the cis-2,6-disubstituted tetrahydropyan. The spiroketal was constructed by addition of a lithiated pyrone 5 to aldehyde 6.

Journal: :Molecules 2008
Guillermo Negrón-Silva C Xochitl Hernández-Reyes Deyanira Angeles-Beltrán Leticia Lomas-Romero Eduardo González-Zamora

A solvent-free approach for the regioselective synthesis of beta-amino alcohols in shorter reaction times and higher yields, compared to conventional heating is described. It involves microwave (MW) exposure of undiluted reactants in the presence of sulphated zirconia (SZ) or sulphated zirconia over MCM-41 (SZM) as catalyst. Both acid materials can be easily recovered and reused.

Journal: :Beilstein Journal of Organic Chemistry 2008
Giuditta Guazzelli Raffaello Lazzaroni Roberta Settambolo

The synthesis of (-)-Indolizidine 167B has been achieved from optically active (R)-3-(pyrrol-1-yl)hex-1-ene. The key step is a highly regioselective hydroformylation reaction and a one-pot intramolecular cyclization providing a general approach to the indolizine nucleus.

2014
Minyan Li Simon Berritt Patrick J. Walsh

A regioselective arylation of 1,1,3-triaryl-2-azaallyl anions with aryl chlorides is described. The palladium-NIXANTPHOS-based catalyst affords diarylmethylamine derivatives in good yield and without product isomerization. A gram scale sequential one-pot ketimine synthesis/arylation protocol was also developed.

Journal: :Organic & biomolecular chemistry 2014
Pathi Suman Bhimapaka China Raju

A facile carbohydrate-based highly stereoselective synthetic route has been developed for the cytospolide P (1) from D-ribose for the first time. Key steps of the synthesis include Wittig homologation, regioselective epoxide ring opening, Sharpless asymmetric epoxidation, Evans aldol reaction, and Yamaguchi macrolactonization.

2017
Veronica Tona Boris Maryasin Aurélien de la Torre Josefine Sprachmann Leticia González Nuno Maulide

Tetrazolium salts are biologically active molecules that have found broad applications in biochemical assays. A regioselective synthesis of tetrazolium salts is described through a formal (3 + 2) cycloaddition. The possibility of employing simple amides and azides as starting material and the mild conditions allow a broad functional group tolerance.

Journal: :Carbohydrate research 2002
Guofeng Gu Yuguo Du Jingqi Pan

An efficient synthesis of buffalo milk pentasaccharide derivative via a 3+2 strategy is described. The use of a trisaccharide isopropyl thioglycoside as a latent glycosyl donor and the application of two well-defined regioselective glycosylations significantly simplified the target preparation.

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