1144528-41-5Relevant articles and documents
Chiral Bipyridine Ligand with Flexible Molecular Recognition Site: Development and Application to Copper-Catalyzed Asymmetric Borylation of α,β-Unsaturated Ketones
Tsutsumi, Ryosuke,Taguchi, Rika,Yamanaka, Masahiro
, (2021/10/20)
A novel chiral bipyridine ligand bearing a flexible side chain with a molecular recognition site enables precise stereocontrol through the cooperative action of metal center and hydrogen bonds. This new chiral ligand was applied to the copper-catalyzed as
Synthesis of fluorine-substituted [2.2]paracyclophane-based carbene precursors for copper-catalyzed enantioselective boration of α,β-unsaturated ketones
Wang, Linyong,Ye, Meng,Wang, Lei,Duan, Wenzeng,Song, Chun,Ma, Yudao
, p. 54 - 61 (2017/01/10)
Fluorine-substituted [2.2]paracyclophane-based carbene precursors have been successfully synthesized and applied to copper-catalyzed asymmetric β-boration of α,β-unsaturated ketones. Fluorination of the planar chiral carbenes has a beneficial impact on th
Synthesis and application of a dual chiral [2.2]paracyclophane-based N-heterocyclic carbene in enantioselective β-boration of acyclic enones
Wang, Lei,Chen, Zhen,Ma, Manyuan,Duan, Wenzeng,Song, Chun,Ma, Yudao
, p. 10691 - 10698 (2015/11/17)
An enantioselective conjugate addition of boron to α,β-unsaturated ketones catalysed by either a N-heterocyclic carbene or a copper-carbene complex generated in situ from a new chiral bicyclic triazolium based on [2.2]paracyclophane is presented. The dual
Heterogeneous versus homogeneous copper(II) catalysis in enantioselective conjugate-addition reactions of boron in water
Kitanosono, Taku,Xu, Pengyu,Kobayashi, Shu
supporting information, p. 179 - 188 (2014/01/06)
We have developed CuII-catalyzed enantioselective conjugate-addition reactions of boron to α,β-unsaturated carbonyl compounds and α,β,γ,δ-unsaturated carbonyl compounds in water. In contrast to the previously reported CuI catalysis that required organic solvents, chiral CuII catalysis was found to proceed efficiently in water. Three catalyst systems have been exploited: cat. 1: Cu(OH)2 with chiral ligand L1; cat. 2: Cu(OH)2 and acetic acid with ligand L1; and cat. 3: Cu(OAc)2 with ligand L1. Whereas cat. 1 is a heterogeneous system, cat. 2 and cat. 3 are homogeneous systems. We tested 27 α,β-unsaturated carbonyl compounds and an α,β-unsaturated nitrile compound, including acyclic and cyclic α,β-unsaturated ketones, acyclic and cyclic β,β- disubstituted enones, acyclic and cyclic α,β-unsaturated esters (including their β,β-disubstituted forms), and acyclic α,β-unsaturated amides (including their β,β-disubstituted forms). We found that cat. 2 and cat. 3 showed high yields and enantioselectivities for almost all substrates. Notably, no catalysts that can tolerate all of these substrates with high yields and high enantioselectivities have been reported for the conjugate addition 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-addition reaction of boron. In addition, the catalyst systems were also applicable to the conjugate addition of boron to α,β,γ, δ-unsaturated carbonyl compounds, although such reactions have previously been very limited in the literature, even in organic solvents. 1,4-Addition products were obtained in high yields and enantioselectivities in the reactions of acyclic α,β,γ,δ-unsaturated carbonyl compounds with diboron 2 by using cat. 1, cat. 2, or cat. 3. On the other hand, in the reactions of cyclic α,β,γ,δ-unsaturated carbonyl compounds with compound 2, whereas 1,4-addition products were exclusively obtained by using cat. 2 or cat. 3, 1,6-addition products were exclusively produced by using cat. 1. Similar unique reactivities and selectivities were also shown in the reactions of cyclic trienones. Finally, the reaction mechanisms of these unique conjugate-addition reactions in water were investigated and we propose stereochemical models that are supported by X-ray crystallography and MS (ESI) analysis. Although the role of water has not been completely revealed, water is expected to be effective in the activation of a borylcopper(II) intermediate and a protonation event subsequent to the nucleophilic addition step, thereby leading to overwhelmingly high catalytic turnover. Copyright
Asymmetric β-boration of α,β-unsaturated carbonyl compounds with chiral Rh[bis(oxazolinyl)phenyl] catalysts
Toribatake, Kenji,Zhou, Li,Tsuruta, Ayae,Nishiyama, Hisao
, p. 3551 - 3560 (2013/05/08)
Chiral rhodium[bis(oxazolinyl)phenyl] complexes exhibited high catalytic activity for the β-boration of α,β-unsaturated esters, ketones, and amides with bis(pinacolato)diboron in the presence of sodium tert-butoxide to attain high enantioselectivity of up to 97%. The substrate scope and catalytic mechanism were discussed.
Synthesis of planar chiral imidazo[1,5-a]pyridinium salts based on [2.2]paracyclophane for asymmetric β-borylation of enones
Hong, Bing,Ma, Yudao,Zhao, Lei,Duan, Wenzeng,He, Fuyan,Song, Chun
experimental part, p. 1055 - 1062 (2011/10/04)
Novel planar chiral pseudo-geminal and pseudo-ortho-oxazoline substituted [2.2]paracyclophanyl imidazo[1,5-a]pyridinium triflates were synthesized. During the synthesis of a pseudo-ortho imidazo[1,5-a]pyridinium triflate based on [2.2]paracyclophane, the
Metal-free catalytic boration at the β-position of α,β-unsaturated compounds: A challenging asymmetric induction
Bonet, Amadeu,Gulyas, Henrik,Fernandez, Elena
supporting information; experimental part, p. 5130 - 5134 (2010/11/04)
Enantiomerlcally 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. (Figure Presented).
Copper-catalyzed enantioselective β-boration of acyclic enones
Sim, Hak-Suk,Feng, Xinhui,Yun, Jaesook
supporting information; experimental part, p. 1939 - 1943 (2009/10/02)
The enantioselective β-boration of various acyclic enones has been studied by using chiral diphosphinecopper complexes. Good to excellent yields and enantioselectivities (up to 97% ee (enantiomeric excess)) were observed for a range of substrates under op
