Metal-Free Catalytic Boration at the β-Position of α,β-Unsaturated Compounds: A Challenging Asymmetric Induction
作者:Amadeu Bonet、Henrik Gulyás、Elena Fernández
DOI:10.1002/anie.201001198
日期:——
Enantiomerically enriched secondary organoboronates containing β‐carbonyl functional groups have been prepared using an unprecedented organocatalytic system (see scheme). The use of chiral tertiary phosphorus compounds induced ee values of up to 95 % in the absence of transition metals.
Catalytic asymmetric synthesis of β-hydroxy ketones by palladium-catalyzed asymmetric 1,4-disilylation of α,β-unsaturated ketones
作者:Yonetatsu Matsumoto、Tamio Hayashi、Yoshihiko Ito
DOI:10.1016/s0040-4020(01)80758-4
日期:1994.1
1,4-Disilylation of β,β-unsaturatedketones with 1,1-dichloro-l-phenyl-2,2,2-trimethyldisilane proceeded in the presence of phosphine-palladium catalysts in benzene. High enantio-selectivity (up to 92%) was observed in the disilylation with dichloro[(R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl]palladium(II) as a catalyst (0.5 mol %). The disilylation products, 1-(trimethyisilyloxy)-3-(dichlorophenylsilyl)propenes
Copper pins on the boron: The enantioselective 1,4‐addition of diboron to α,β‐unsaturatedcompounds proceeds smoothly in the presence of catalytic amounts of Cu(OH)2 and chiral 2,2′‐bipyridine ligand in water. A wide substrate scope of α,β‐unsaturatedcarbonylcompounds, including acyclic, cyclic, and β,β‐disubstituted enones, α,β‐unsaturated esters, amides, and a nitrile, has been shown.
Synthesis of new chiral keto alcohols by baker’s yeast
作者:Tülay Yıldız、Nurgül Çanta、Ayşe Yusufoğlu
DOI:10.1016/j.tetasy.2014.01.003
日期:2014.2
Fourteen chiral α- and β-keto alcohols 2a–2r were synthesized by the asymmetric reduction of their corresponding diketones 1a–1r viabaker’s yeast. In addition, ten corresponding racemic α-keto alcohols were synthesized by the benzoin condensation of their corresponding aldehydes, which were used for the determination of the ee values through their chiral resolution on chiral HPLC. Amongst the 15 diketones
The unique nature and readily availability of Cu(v) species underscores the value of the Cu(v)-based catalyst over an array of well-documented Cu(i)-based catalysts.