我们通过内部二烯与Piers硼烷HB(C 6 F 5)2和类似物HB(p- C 6 F 4 H)2的加成反应制备了新型的手性C 2对称双环双硼烷催化剂。加料方式对反应温度的依赖性使我们能够从单一的二烯前体中选择性地制备两种非对映体催化剂。原位制备的双硼烷在亚胺加氢反应中表现出出色的活性(在-40°C时的转换数高达200)和对映选择性(高达95% ee)。
Chiral phosphine-phosphoramidite ligands for highly enantioselective hydrogenation of N-arylimines
作者:Qing Li、Chuan-Jin Hou、Xiao-Ning Liu、De-Zhi Huang、Yan-Jun Liu、Rui-Feng Yang、Xiang-Ping Hu
DOI:10.1039/c4ra16062b
日期:——
The asymmetrichydrogenation of N-arylimines with the chiral phosphine-phosphoramidite ligand, (Sc,Sa)-PEAPhos 2b, has been developed. The results revealed that the presence of the substituents on the 3,3′-positions of the binaphthyl backbone significantly improved the enantioselectivity. The utility of this methodology was demonstrated in the synthesis of the chiral fungicide (R)-metalaxyl.
Direct and indirect reductive amination of aldehydes and ketones with solid acid-activated sodium borohydride under solvent-free conditions
作者:Byung Tae Cho、Sang Kyu Kang
DOI:10.1016/j.tet.2005.04.039
日期:2005.6
A simple and convenient procedure for reductive amination of aldehydes and ketonesusingsodiumborohydride activated by boric acid, p-toluenesulfonic acid monohydrate or benzoic acid as reducing agent under solvent-free conditions is described.
Commercial Supported Gold Nanoparticles Catalyzed Alkyne Hydroamination and Indole Synthesis
作者:Shengzong Liang、Luisa Hammond、Bo Xu、Gerald B. Hammond
DOI:10.1002/adsc.201600804
日期:2016.10.20
on titanium dioxide (TiO2) were found to be a highly efficient catalyst for alkynehydroamination. Terminal alkynes could easily undergo intermolecularhydroamination with low catalyst loadings (0.2 mol% Au) under solvent‐free conditions. Indoles were efficiently synthesized using microwave heating through intramolecular hydroamination.
Role of Noncovalent Interactions in the Enantioselective Reduction of Aromatic Ketimines with Trichlorosilane
作者:Andrei V. Malkov、Andrea Mariani、Kenneth N. MacDougall、Pavel Kočovský
DOI:10.1021/ol049213+
日期:2004.6.1
[reaction: see text] Asymmetric reduction of ketimines 1 with trichlorosilane can be catalyzed by a new N-methyl L-valine derived Lewis basic organocatalyst, such as 4d, with high enantioselectivity. The structure-reactivity investigation suggests hydrogen bonding and arene-arene interactions between the catalyst and the incoming imine as the main factor determining the enantiofacial selectivity.
Direct Catalytic Access to N-Silylated Enamines from Enolizable Imines and Hydrosilanes by Base-Free Dehydrogenative SiN Coupling
作者:Julia Hermeke、Hendrik F. T. Klare、Martin Oestreich
DOI:10.1002/chem.201402866
日期:2014.7.21
α‐proton rather than α‐deprotonation of the enolizable imine followed by reaction with an electrophilic silicon reagent. The silicon electrophile, stabilized by a sulfur atom, is generated by cooperative activation of an SiH bond at the RuS bond of a tethered ruthenium(II) thiolate complex. After transfer of the silicon cation onto the imine nitrogen atom, the remaining ruthenium(II) hydride fulfills