Enantioselective Synthesis of Quaternary α-Amino Acids via <scp>l</scp>-<i>tert</i>-Leucine-Derived Squaramide-Catalyzed Conjugate Addition of α-Nitrocarboxylates to Enones
作者:Kalisankar Bera、Nishikant S. Satam、Irishi N. N. Namboothiri
DOI:10.1021/acs.joc.6b00543
日期:2016.7.1
Enantioselective Michael addition of tertiary α-nitroesters to β-unsubstituted vinyl ketones has been carried out in the presence of an l-tert-leucine-derived squaramide as organocatalyst. The products, quaternary α-nitroesters, were formed in excellent yield and moderate to good ee’s in most cases. Scale-up of the reaction and synthetic applications of the products, including transformation to representative
A copper-catalyzed asymmetrichydrosilylation of β-nitroethyl aryl ketones has been disclosed, and the corresponding chiral alcohols could be obtained in high yields (up to 99% yield) and excellent enantioselectivities (up to 96% ee). Moreover, the reaction worked well on a gram scale with 0.3 mol % of ligand loading, indicating that our protocol has potential applications in the synthesis of important
Iron-Catalyzed α-Methylenation of Ketones with<i>N</i>,<i>N</i>-Dimethylacetamide: An Approach for α,β-Unsaturated Carbonyl Compounds
作者:Yi-Ming Li、Shao-Jie Lou、Qin-Hua Zhou、Lian-Wen Zhu、Long-Feng Zhu、Lei Li
DOI:10.1002/ejoc.201500189
日期:2015.5
this study, we developed a general iron-catalyzedα-methylenation of ketones by using N,N-dimethylacetamide as the one-carbon source. Various ketones, including aryl and alkyl ketones, enones, and dicarbonyl compounds were well tolerated to yield the corresponding α,β-unsaturatedcarbonylcompounds in the presence of an iron catalyst, peroxides, and N,N-dimethylacetamide under aerobic conditions.
N-Heterocyclic carbene-catalyzed double acylation of enones with benzils
作者:Ken Takaki、Akira Ohno、Makoto Hino、Takashi Shitaoka、Kimihiro Komeyama、Hiroto Yoshida
DOI:10.1039/c4cc05436a
日期:——
Thiazolium carbene-catalyzed reaction of aromatic 1,2-diketones with enones in aprotic solvents gave double acylation products in good yields, whereas hydroacylation products were not detected at all.