New asymmetricconjugatereduction of beta,beta-disubstituted alpha,beta-unsaturated ketones and esters was accomplished with alkoxylhydrosilanes in the presence of chiral rhodium(2,6-bisoxazolinylphenyl) complexes in high yields and high enantioselectivity. (E)-4-Phenyl-3-penten-2-one and (E)-4-phenyl-4-isopropyl-3-penten-2-one were readily reduced at 60 degrees C in 95 % ee and 98 % ee, respectively
Rhodium-catalyzed asymmetric synthesis of β-branched esters from allylic amines
作者:Summer D. Laffoon、Zhao Wu、Kami L. Hull
DOI:10.1039/c8cc02612b
日期:——
Allylic amines are converted to chiral, β-branched esters under rhodium catalysis in the presence of alcohol nucleophiles. Allylic amines with aliphatic and aromatic vinylic substituents are converted to ester products with excellent enantioselectivities in all cases. Several alcohol nucleophiles have been utilized in the reaction including 1° and 2° derivatives.
Chiral rhodium(bisoxazolinylphenyl) complexes reduced α,β-unsaturatedesters in high enantioselectivity up to 97-98% ee in the combination of alkoxyhydrosilanes.
Azabis(oxazolines) prove to be superior ligands for the enantioselective, cobalt(II)-catalyzed conjugatereduction of α,β-unsaturated carbonylcompounds with sodium borohydride. β-Trisubstituted α,β-unsaturated esters and amides as well as γ-butenolides are readily converted to their corresponding saturated counterparts with enantioselectivities up to 97% ee.
[EN] PPAR AGONISTS, COMPOUNDS, PHARMACEUTICAL COMPOSITIONS, AND METHODS OF USE THEREOF<br/>[FR] AGONISTES DE PPAR, COMPOSÉS, COMPOSITIONS PHARMACEUTIQUES ET MÉTHODES D'UTILISATION DE CEUX-CI