A catalytic asymmetric carbonyl-ene reaction of [small beta],[gamma]-unsaturated [small alpha]-ketoesters with 5-methyleneoxazolines was accomplished. The process was based on the utilization of a chiral N,N'-dioxide/MgII catalyst, providing the desired products with excellent...
F<sup>–</sup>-Free Deoxyhydrotrifluoromethylation of α-Keto Esters with Ph<sub>3</sub>P<sup>+</sup>CF<sub>2</sub>CO<sub>2</sub><sup>–</sup>: Synthesis of α–CF<sub>3</sub>-Substituted Esters
作者:Ying Zheng、Yimin Jia、Yuan Yuan、Zhong-Xing Jiang、Zhigang Yang
DOI:10.1021/acs.joc.0c01518
日期:2020.8.21
direct deoxyhydrotrifluoromethylation of α-keto esters with a difluoromethylating reagent has been achieved, in which the employment of water can promote the dissociation of the CF2 group to form a CF3 moiety, which provides the successful transformation. The current protocol demonstrates one of the most practical approaches to generate α-trifluoromethyl esters with a broad substrate scope and high functional
Here we report an efficient asymmetric [4+2] cycloaddition of β,γ-unsaturated α-ketoesters with cyclobutenones. The corresponding products were obtained in good yields (up to 92%) with excellent enantioselectivities (up to 98% ee) and diastereoselectivities (up to >19/1 dr). Moreover, based on the control experiments and previous reports, a possible catalytic cycle was proposed.
Synthesis of Chiral α,β-Unsaturated γ-Amino Esters via Pd-Catalyzed Asymmetric Allylic Amination
作者:Chao Xia、Jiefeng Shen、Delong Liu、Wanbin Zhang
DOI:10.1021/acs.orglett.7b01904
日期:2017.8.18
A Pd-catalyzed asymmetricallylic amination of 4-substituted 2-acetoxybut-3-enoates with amines has been developed for the regiospecific synthesis of chiral α,β-unsaturated γ-amino esters. The desired chiral aminated products can be obtained in up to 98% yield, and 99% ee and can be conveniently transformed to chiral γ-amino acid/alcohol derivatives and chiral γ-lactams, which can then be subjected
Facile synthesis of substituted diaryl sulfones <i>via</i> a [3 + 3] benzannulation strategy
作者:Xiang-zheng Tang、Lang Tong、Hua-ju Liang、Jie Liang、Yong Zou、Xue-jing Zhang、Ming Yan、Albert S. C. Chan
DOI:10.1039/c8ob00662h
日期:——
base-mediated [3 + 3] benzannulation strategy for the conversion of 1,3-bis(sulfonyl)propenes and β,γ-unsaturated α-ketoesters to diaryl sulfones has been developed. This method provides facile, metal-free and efficient access to highly substituted diaryl sulfones in good to excellent yields. In addition, the sulfonyl group could be easily removed or converted to other functional groups via an organostannane