Impregnated Copper on Magnetite as Recyclable Catalyst for the Addition of Alkoxy Diboron Reagents to C−C Double Bonds
作者:Rafael Cano、Diego J. Ramón、Miguel Yus
DOI:10.1021/jo100325e
日期:2010.5.21
A simple protocol for the borylation with use of impregnated copper on magnetite is described. The reactions showed a very broad scope and all type of olefins could be used with similar results. The catalyst could be easily removed by a magnet and it could be reused several times, showing similar activity.
Catalytic enantioselective boron conjugate addition to cyclic carbonyl compounds: a new approach to cyclic β-hydroxy carbonyls
作者:Xinhui Feng、Jaesook Yun
DOI:10.1039/b914207j
日期:——
The highly enantioselective conjugate boration of six-membered and seven-membered cyclicenones and unsaturated esters was achieved by the use of a copper-(R,S)-Taniaphos complex with up to 99% ee under optimal conditions.
The use of phosphines to assist the organocatalytic β-boration reaction of α,β-unsaturated carbonyl compounds has been demonstrated with a selected number of substrates. The new method eludes the use of Brönsted bases to promote the catalytic active species and PR3 becomes essential to interact with the substrate resulting in the formation of a zwitterionic phosphonium enolate. This species can further deprotonate MeOH when B2pin2 is present forming eventually the ion pair [α-(H),β-(PR3)-ketone]+[B2pin2·MeO]â that is responsible for the catalysis.
Heterogeneous versus Homogeneous Copper(II) Catalysis in Enantioselective Conjugate-Addition Reactions of Boron in Water
作者:Taku Kitanosono、Pengyu Xu、Shū Kobayashi
DOI:10.1002/asia.201300997
日期:2014.1
reported for the conjugateaddition of boron. Heterogeneous cat. 1 also gave high yields and enantioselectivities with some substrates and also gave the highest TOF (43 200 h−1) for an asymmetric conjugate‐additionreaction of boron. In addition, the catalyst systems were also applicable to the conjugateaddition of boron to α,β,γ,δ‐unsaturated carbonyl compounds, although such reactions have previously