N-phenylimine of 4-trifluoromethylphenylmethylketone;Benzenamine, N-[1-[4-(trifluoromethyl)phenyl]ethylidene]-;N-phenyl-1-[4-(trifluoromethyl)phenyl]ethanimine
The behavior of readily synthesized and even commercially available (S)-proline derivatives, was studied in the trichlorosilane-mediated reduction of ketoimines. A small library of structurally and electronically modified chiral Lewis bases was considered; such compounds were shown to promote the enantioselective reduction of different substrates in good chemical yields. In the HSiCl3 addition to the model substrate N-phenylacetophenone imine, the organocatalyst of choice led to the formation of the corresponding amine with good stereoselectivity, up to 75% ee. Theoretical studies were also performed in order to elucidate the origin of the stereoselection.
1H NMR, in situ, determines the enantiomericexcess of reduced chiral alcohols or amines without adding any auxiliary and workup. The percent ee data determined by this method agree well with those given by HPLC. This approach may be potentially applicable to many asymmetric reductions.
1 H NMR原位确定还原的手性醇或胺的对映体过量,而无需添加任何助剂和后处理。通过此方法确定的ee百分比数据与HPLC给出的数据非常吻合。此方法可能潜在地适用于许多不对称折减。
l-Pipecolinic acid derived Lewis base organocatalyst for asymmetric reduction of N-aryl imines by trichlorosilane: effects of the side amide group on catalytic performances
作者:Zhouyu Wang、Chao Wang、Li Zhou、Jian Sun
DOI:10.1039/c2ob26772a
日期:——
A series of N-formamides derived from pipecolinic acid have been synthesized and tested as Lewisbase catalysts for the enantioselective reduction of N-aryl imines by trichlorosilane. Through the investigation of the structure–efficacy relationship between the side amide group and catalytic performance, several highly effective catalysts were discovered. In particular, arylamido-type catalyst 5i and
A rhenium complex, [ReBr(CO) 3 (thf)] 2 , catalyzes the insertion of α,β-unsaturated carbonyl compounds into a C-H bond of aromatic compounds having nitrogen-containing directing groups. In this reaction, Re 2 (CO) 10 can also be used as a catalyst. When imines are employed as the aromatic substrates, sequential cyclization proceeds and indene derivatives are obtained in good to excellent yields. This
1,1′-Binaphthyldiamine-Based Lewis Bases as Readily Available and Efficient Organocatalysts for the Reduction of<i>N</i>-Aryl and<i>N</i>-Alkyl Ketimines
development of simple, low-cost, efficient, and sustainable routes to enantiomerically pure amines is a topic of extraordinary interest, specially in view of future industrial applications. In this context, we wish to report a chemical and stereochemical efficient synthesis of chiral amines through the Lewis base activated trichlorosilane reduction of ketimines. An organocatalyst, easily prepared in a single