Catalytic enantioselective arylations: boron to zinc exchange as a powerful tool for the generation of transferable aryl groups

The transmetalation between boron and zinc is of great importance for application in organic synthesis, since it allows the formation of new carbon-carbon bonds between organometallic units and electrophiles. The direct arylation of aldehydes or more scarcely ketones, in a catalytic, enantioselective manner using chiral catalysts has been described recently. The enantiomerically enriched diarylmethanols obtained in these reactions are valuable precursors for important bioactive molecules. This review provides a synopsis of this ever-growing field and highlights some of the challenges that still remain.A transmetalação entre boro e zinco apresenta uma grande importância para diversas aplicações em síntese orgânica, uma vez que permite a formação de novas ligações carbono-carbono entre reagentes organometálicos e espécies eletrofílicas. A arilação direta de aldeídos e, mais raramente de cetonas, de maneira catalítica e enantiosseletiva, empregando catalisadores quirais, têm sido descrita recentemente. Os diaril metanóis opticamente enriquecidos, obtidos nessas reações são precursores valiosos para a síntese de moléculas bioativas. O presente trabalho apresenta uma revisão sobre essa crescente área de atuação e destaca alguns dos desafios que ainda permanecem.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)CNPqFAPES

[(2S,5R)-1-Methyl-5-phenyl­pyrrolidin-2-yl]diphenyl­methanol

In the title compound, C24H25NO, the phenyl and diphenyl­methanol substituents are syn to each other. The pyrrolidine ring has an envelope conformation with the flap atom being the C atom bearing the phenyl substituent. The hy­droxy group forms an intra­molecular hydrogen bond with the pyrrolidine N atom, and the phenyl rings lie to same side of the mol­ecule. The crystal packing features C—H⋯π inter­actions. Two slightly displaced co-planar orientations were found for one of the phenyl rings; the major component had a site-occupancy factor of 0.782 (15)

Chalcogen-containing oxazolines in the palladium-catalyzed asymmetric allylic alkylation

A comparative study about the ability of chiral chalcogen-containing oxazolines to act as chiral ligands in the palladium-catalyzed allylic alkylation of rac-1,3-diphenyl-2-propenyl acetate with dimethyl malonate is reported. Differences in the catalytic performance are observed with sulfur, selenium and tellurium analogues

Synthesis of Alkylseleno-Carbohydrates and Evaluation of their Antioxidant Properties

In the present study, we describe the synthesis of alkylseleno carbohydrates with different sugar scaffolds and the evaluation of their antioxidant activity profile. A compound possessing a C8 alkyl chain presented the best results in the free radical scavenging activity

Chiral triphenylprolinol ligands for the efficient catalytic asymmetric arylation of aldehydes

The synthesis of new chiral amino alcohols by Heck arylation of an enecarbamate is described. These compounds were used as chiral ligands for the catalytic asymmetric arylation of aldehydes and can be easily recovered. Chiral, nonracemic diarylmethanols were obtained in high yields and enantioselectivities1936963703CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPNão temNão te