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1.
Org Lett ; 21(22): 9198-9202, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31647672

RESUMO

This communication highlights the use of chiral sulfinamides as nitrogen nucleophiles in intermolecular aza-Michael reactions. When chiral sulfinamides are coupled to a chloroethyl group, the corresponding novel annulating reagents can be used to streamline the stereoselective synthesis of complex pyrrolidine-containing molecules. As a result, it has enabled a medicinal chemistry campaign for the synthesis of biologically active RORγt inverse agonists.

2.
Angew Chem Int Ed Engl ; 58(47): 17068-17073, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31538388

RESUMO

We report the development of palladium(0)-catalyzed syn-selective 1,2-carboboration and -silylation reactions of alkenes containing cleavable directing groups. With B2 pin2 or PhMe2 Si-Bpin as nucleophiles and aryl/alkenyl triflates as electrophiles, a broad range of mono-, di-, tri- and tetrasubstituted alkenes are compatible in these transformations. We further describe a directed dearomative 1,2-carboboration of electron-rich heteroarenes by employing this approach. Through use of a removable chiral directing group, we demonstrate the viability of achieving stereoinduction in Heck-type alkene 1,2-difunctionalization. This work introduces new avenues to access highly functionalized boronates and silanes with precise regio- and stereocontrol.

3.
ACS Catal ; 8(4): 2897-2901, 2018 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-31485379

RESUMO

A Pt-catalyzed enantioselective hydrosilylation of alkenylboronates is described. This reaction occurs with high regio- and enantioselectivity, providing a convenient route to chiral non-racemic geminal silylboronates. These compounds are useful reagents in stereoselective synthesis.

4.
J Org Chem ; 82(13): 7040-7044, 2017 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-28594174

RESUMO

Conditions have been developed for the palladium-catalyzed cyanation of aryl bromides utilizing the air-stable XantPhos-PdCl2 precatalyst. By employing a trialkylamine as a reducing agent, the active Pd(0) species is generated in situ, alleviating the need to employ the air-sensitive Pd2(dba)3. Twenty-two substituted benzonitriles have been synthesized using this method.

5.
Angew Chem Int Ed Engl ; 55(8): 2636-49, 2016 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-26764019

RESUMO

Terminal alkenes are readily available functional groups which appear in α-olefins produced by the chemical industry, and they appear in the products of many contemporary synthetic reactions. While the organic transformations that apply to alkenes are amongst the most studied reactions in all of chemical synthesis, the number of reactions that apply to nonactivated terminal alkenes in a catalytic enantioselective fashion is small in number. This Minireview highlights the cases where stereocontrol in catalytic reactions of 1-alkenes is high enough to be useful for asymmetric synthesis.


Assuntos
Alcenos/química , Catálise , Estereoisomerismo
6.
Org Lett ; 17(7): 1708-11, 2015 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-25799147

RESUMO

A highly stereoselective boron-Wittig reaction between stable and readily accessible 1,1-bis(pinacolboronates) and aldehydes furnishes a variety of synthetically useful di- and trisubstituted vinyl boronate esters.


Assuntos
Aldeídos/química , Boro/química , Ácidos Borônicos/síntese química , Compostos de Vinila/síntese química , Ácidos Borônicos/química , Estrutura Molecular , Estereoisomerismo , Compostos de Vinila/química
7.
J Am Chem Soc ; 136(46): 16140-3, 2014 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-25387002

RESUMO

The catalytic enantioselective diboration of vinyl boronate esters furnishes chiral tris(boronates) in a selective fashion. Subsequent deborylative alkylation occurs in a diastereoselective fashion, both for intermolecular and intramolecular processes.


Assuntos
Ácidos Borônicos/química , Alquilação , Catálise , Ésteres , Indicadores e Reagentes/química , Estereoisomerismo , Especificidade por Substrato
8.
Org Lett ; 16(17): 4420-3, 2014 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-25105510

RESUMO

Aryl electrophiles containing tethered allylboronate units undergo efficient intramolecular coupling in the presence of a chiral palladium catalyst to give enantioenriched carbocyclic products. The reaction is found to be quite general, affording 5, 6, and 7-membered carbocyclic products as single regioisomers and with moderate enantioselectivities. Examination of differential coupling partners points to rapid allyl-equilibration as a key stereodefining feature.


Assuntos
Ácidos Borônicos/química , Paládio/química , Compostos Policíclicos/síntese química , Catálise , Ciclização , Estrutura Molecular , Compostos Policíclicos/química , Estereoisomerismo
9.
J Am Chem Soc ; 135(30): 11222-31, 2013 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-23862690

RESUMO

The Pt-catalyzed enantioselective diboration of terminal alkenes can be accomplished in an enantioselective fashion in the presence of chiral phosphonite ligands. Optimal procedures and the substrate scope of this transformation are fully investigated. Reaction progress kinetic analysis and kinetic isotope effects suggest that the stereodefining step in the catalytic cycle is olefin migratory insertion into a Pt-B bond. Density functional theory analysis, combined with other experimental data, suggests that the insertion reaction positions platinum at the internal carbon of the substrate. A stereochemical model for this reaction is advanced that is in line both with these features and with the crystal structure of a Pt-ligand complex.


Assuntos
Alcenos/química , Boratos/química , Platina/química , Catálise , Cinética , Ligantes , Modelos Moleculares , Conformação Molecular , Oxirredução , Estereoisomerismo , Especificidade por Substrato
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