نتایج جستجو برای: diastereoselective synthesis

تعداد نتایج: 409824  

Journal: :Angewandte Chemie 2012
Matthew J Hesse Craig P Butts Christine L Willis Varinder K Aggarwal

E-allylic boronic esters undergo a highly diastereoselective protodeboronation with TBAF⋅3 H(2)O to give Z-trisubstituted alkenes. The selectivity can be switched to give predominantly the E-alkene instead by using KHF(2)/TsOH (see scheme). The utility of the methodology has been illustrated in a short synthesis of a component of the sex pheromone of the Californian red scale beetle.

Journal: :Organic & biomolecular chemistry 2011
Thomas J K Findley David Sucunza Laura C Miller Matthew D Helm Madeleine Helliwell David T Davies David J Procter

The cis-hydrindane motif is found in a number of natural products that display important biological activity. A flexible, stereoselective approach to the framework has been developed that features highly diastereoselective, SmI(2)-mediated cyclisations. The strategy has been exploited in the first synthesis of the proposed structure of faurinone and an approach to the skeleton of the antibacter...

Journal: :Organic & biomolecular chemistry 2014
Gangarajula Sudhakar Shruthi Bayya Vilas D Kadam Jagadeesh Babu Nanubolu

The first stereoselective total synthesis of gonytolide C, which is a monomeric unit of an innate immune promoter gonytolide A, has been accomplished from the aldol reaction between acetophenone derived from orcinol and butyrolactone containing α-keto ester followed by the excellent diastereoselective intramolecular cyclization. The first total synthesis of gonytolide G has been achieved by the...

Journal: :Advanced Synthesis & Catalysis 2021

A diastereoselective and enantioselective construction of 2,3-disubstituted 1,4-dicarbonyl compounds is reported. Nishiyama's RuPhebox complex (2.0 mol% catalyst loading) serves as a chiral Lewis acid in conjunction with BrCCl3 base for the oxidative homocoupling 2-acyl imidazoles via stereocontrolled reaction intermediate Ru enolates situ brominated imidazoles. Cleavage achiral imidazole auxil...

2014
Michael R. Harris Mikhail O. Konev Elizabeth R. Jarvo

Enantioenriched methylenecyclopentanes are synthesized by stereospecific, nickel-catalyzed Heck cyclizations of secondary benzylic ethers. The reaction proceeds in high yield and enantiospecificity for benzylic ethers of both π-extended and simple arenes. Ethers with pendant 1,2-disubstituted olefins form trisubstituted olefins with control of both absolute configuration and alkene geometry. Di...

Journal: :Chemical communications 2016
A N Baumann A Music K Karaghiosoff D Didier

A simple and efficient diastereoselective synthesis of methylenecyclopropanes is described, in which boron-homologation and allylboration are merged into a one-pot process, starting from in situ generated cyclopropenyllithium species. This unprecedented methodology opens a new route to strained alkylidenecycloalkanes containing a quaternary stereocenter, in high yields and excellent diastereome...

Journal: :The Journal of organic chemistry 2005
Marta Rosillo Gema Domínguez Luis Casarrubios Javier Pérez-Castells

[reactions: see text] We show the use of arene-chromium tricarbonyl complexes in intra- and intermolecular Pauson-Khand reactions. Both styrene and ethynylbenzene complexes react with alkynes and olefins. The synthesis of enynes connected through chromium-complexed aromatic rings is developed. The intramolecular Pauson-Khand reaction occurs in a totally diastereoselective manner.

2013
Martin Zahel Peter Metz

(-)-Oxyphyllol was prepared in only 4 steps from an epoxy enone that already served as an intermediate for the total synthesis of the anticancer guaiane (-)-englerin A. A regio- and diastereoselective Co(II)-catalyzed hydration of the olefin and a transannular epoxide opening were used as the key reactions.

Journal: :Chemical communications 2012
Atul K Singh Ruchi Chawla Ankita Rai Lal Dhar S Yadav

NHC-catalysed azalactone ring-opening and piperidine ring-closing cascade with α,β-unsaturated aldehydes (enals) in a one-pot operation is reported. The present reaction cascade offers a convenient method for a highly diastereoselective synthesis of multifunctionalised piperidines in excellent yields under mild conditions.

Journal: :Chemical communications 2015
Sengodagounder Muthusamy Manickasamy Sivaguru Eringathodi Suresh

An atom-economical diastereoselective synthesis of indenodithiepines and indenodithiocines has been developed via a domino reaction of propargylic alcohols and dithioacetals in the presence of InCl3 as a catalyst. A range of functionalized dithiepines and dithiocines, fused to the indene ring, were obtained in good to excellent yields under mild conditions.

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