Annulation of α,β-Unsaturated Imines and Alkynes via Cobalt-Catalyzed Olefinic C–H Activation
作者:Takeshi Yamakawa、Naohiko Yoshikai
DOI:10.1021/ol303259m
日期:2013.1.4
internal alkyne to afford a polysubstituted dihydropyridine derivative in good yield under mild conditions. The reaction likely involves alkenylation of the olefinic C–H bond via cobalt-mediated nitrogen-assisted C–H activation followed by facile 6πelectrocyclization of the resulting azatriene intermediate.
Organocatalysis with a Fluorous Tag: Asymmetric Reduction of Imines with Trichlorosilane Catalyzed by Amino Acid-Derived Formamides
作者:Andrei V. Malkov、Marek Figlus、Sigitas Stončius、Pavel Kočovský
DOI:10.1021/jo062215i
日期:2007.2.1
Asymmetricreduction of ketimines 1 with trichlorosilane can be catalyzed by N-methylvaline-derived Lewis-basic formamides 3a−d with high enantioselectivity (≤95% ee) and low catalyst loading (1−5 mol %) at room temperature in toluene. Appending a fluorous tag, as in 5a−c, simplifies the isolation procedure, while preserving high enantioselectivity (≤92% ee).
Highly Enantioselective Hydrogenation of<i>N</i>-Aryl Imines Derived from Acetophenones by Using Ru-Pybox Complexes under Hydrogenation or Transfer Hydrogenation Conditions in Isopropanol
The asymmetric reduction of N‐arylimines derived from acetophenones by using Ru complexes bearing both a pybox (2,6‐bis(oxazoline)pyridine) and a monodentate phosphite ligand has been described. The catalysts show good activity with a diverse range of substrates, and deliver the amine products in very high levels of enantioselectivity (up to 99 %) under both hydrogenation and transfer hydrogenation
Direct Transformation of Methyl Imines to α-Iminonitriles under Mild and Transition-Metal-Free Conditions
作者:Feng Chen、Xiaoqiang Huang、Yuxin Cui、Ning Jiao
DOI:10.1002/chem.201301933
日期:2013.8.19
A novel transformation of methyl imines into α‐iminonitriles undermild and transition‐metal‐free conditions is described. Three CH bonds are cleaved in a radical pathway at room temperature under air. Simple bromide salts are employed to assist this radical process (see scheme; FG=functional group, PIDA = iodobenzene diacetate, TMS = trimethylsilyl).