Catalytic Asymmetric Transfer Hydrogenation of <i>trans</i>-Chalcone Derivatives Using BINOL-derived Boro-phosphates
作者:Fei Na、Susana S. Lopez、Alice Beauseigneur、Lucas W. Hernandez、Zhuoxin Sun、Jon C. Antilla
DOI:10.1021/acs.orglett.0c02042
日期:2020.8.7
Chiral phosphoric-acid-catalyzed asymmetric reductions of trans-chalcones have been investigated in this work. A BINOL-derived boro-phosphate-catalyzed asymmetric transfer hydrogenation of the carbon–carbon double bond of trans-chalcone derivatives employing borane as a hydride source was realized. This methodology provides a convenient procedure to accesschiral dihydrochalone derivatives in high
Catalytic asymmetric construction of tetrasubstituted carbon stereocenters by conjugate addition of dialkyl phosphine oxides to β,β-disubstituted α,β-unsaturated carbonyl compounds
作者:Depeng Zhao、Lijuan Mao、Linqing Wang、Dongxu Yang、Rui Wang
DOI:10.1039/c1cc16079f
日期:——
The catalytic asymmetric phospha-Michael reaction of dialkyl phosphine oxides with beta,beta-disubstituted alpha,beta-unsaturated carbonyl compounds was achieved. The products bearing tetrasubstituted carbon stereocenters were obtained in high yields with excellent enantioselectivities (up to >99% ee).
Lewis Base-Catalyzed Enantioselective Conjugate Reduction of β,β-Disubstituted α,β-Unsaturated Ketones with Trichlorosilane: <i>E</i>/<i>Z</i>-Isomerization, Regioselectivity, and Synthetic Applications
The chiral bisphosphine dioxide-catalyzed asymmetric conjugate reduction of acyclic β,β-disubstituted α,β-unsaturatedketones with trichlorosilane affords saturated ketones having a stereogenic carbon center at the carbonyl β-position with high enantioselectivities. Because the E/Z-isomerizations of enone substrates occur concomitantly, reduction products with the same absolute configurations are obtained
β-unsaturated ketones to access various enantiomerically enriched cyclic allylic alcohols under mild conditions, catalyzed by in situ generated copper hydride ligated with (R)-DTBM-C3*-TunePhos. α-Brominated cycloalkenones were reduced with excellent enantioselectivities of up to 98% ee, while substrates that were without α-substituents were reduced chemoselectively, with moderate enantioselectivities.
我们报告了环状 α,β-不饱和酮的不对称 1,2-还原,以在温和条件下获得各种对映体富集的环状烯丙醇,由原位生成的与 ( R )-DTBM-C 3 *-TunePhos连接的氢化铜催化。α-溴化环烯酮被还原,具有高达 98% ee 的出色对映选择性,而不含 α-取代基的底物被化学选择性还原,具有中等对映选择性。
Direct Aroylation of Olefins through a Cobalt/Photoredox‐Catalyzed Decarboxylative and Dehydrogenative Coupling with α‐Oxo Acids
作者:Alex M. Davies、Rafael D. Hernandez、Jon A. Tunge
DOI:10.1002/chem.202202781
日期:2022.12.27
Visible light promotes decarboxylative Heck-like benzoylations of olefins. This process leverages the synergistic interaction of a photoredox catalyst with cobaloxime catalysts to form enones through decarboxylation and hydrogen evolution. Mechanistic studies reveal different rate-limiting steps, depending on electronics of the olefin.