Novel Chiral Bisformamide-Promoted Asymmetric Allylation of Benzaldehyde with Allyltrichlorosilane
摘要:
Novel chiral bisformamides have been prepared from (R,R)-1,2-cyclohexanediamine and utilized as Lewis bases in the asymmetric allylation of benzaldehyde with allyltrichlorosilane. The reaction in the presence of Lewis base 1i gave an 83:17 enantiomeric ratio (R/S) of the products in 90% isolated yield.
Nickel(II)‐Catalyzed Diastereo‐ and Enantioselective Michael/ Hemiacetalization Cascade Reaction of α‐Ketoesters with 2‐(2‐Nitrovinyl)phenols
作者:Long Chen、Wu‐Lin Yang、Jia‐Huan Shen、Wei‐Ping Deng
DOI:10.1002/adsc.201900753
日期:2019.10.8
A nickel(II)/diamine‐catalyzed diastereo‐ and enantioselective Michael/hemiacetalization cascade reaction of α‐ketoesters with 2‐(2‐nitrovinyl)phenols has been established, thus providing a range of structurally diverse polysubstituted chromanes in good yields and excellent stereoselectivities (up to 89% yield, >20:1 dr, >99% ee). Moreover, the gram‐scale experiment was performed with only 0.5 mol%
Asymmetricprotonation of ketone enolates is a convenient alternative to asymmetric alkylation of enolates that allows to convert racemic ketones into their optically active form. Here, we have reported an efficient enantioselective protonation of 2-methyl-1-tetralone lithium enolate catalyzed by salan-type diamines. A broad series of salan-type catalysts were synthesized, including several previously
Nickel(II)-Catalyzed Diastereo- and Enantioselective [3+2] Cycloaddition of α-Ketoesters with 2-Nitrovinylindoles and 2-Nitrovinylpyrroles
作者:Wu-Lin Yang、Zhong-Tao Sun、Hao Sun、Wei-Ping Deng
DOI:10.1002/cjoc.201800572
日期:2019.3
The catalyticasymmetric [3+2] cycloaddition of α‐ketoesters with 2‐nitrovinylindoles and 2‐nitrovinyl‐ pyrroles has been established. This strategy allowed the construction of structurally diverse pyrrolo[1,2‐a]indoles bearing three contiguous stereocenters in generally high yields and good to excellent stereoselectivities (up to 98% yield, > 98 : 2 dr, 99% ee). The efficient synthesis of tetracyclic
建立了α-酮酸酯与2-硝基乙烯基吲哚和2-硝基乙烯基吡咯的催化不对称[3 + 2]环加成反应。该策略允许构建具有三个连续立体中心的结构多样的吡咯并[1,2- a ]吲哚,且通常具有高产率和良好至优异的立体选择性(产率高达98%,> 98:2 dr,99%ee)。通过环加合物的衍生化有效合成四环精神化合物类似物显示了该策略的巨大合成潜力。
Ni-Catalyzed Dual C–H Annulation of Benzimidazoles with Alkynes for Synthesis of π-Extended Heteroarenes
作者:Shao-Long Qi、Yue Li、Jiang-Fei Li、Tao Zhang、Yu-Xin Luan、Mengchun Ye
DOI:10.1021/acs.orglett.1c01253
日期:2021.5.21
Nickel-Catalyzed Asymmetric <i>C</i>-Alkylation of Nitroalkanes: Synthesis of Enantioenriched β-Nitroamides
作者:Vijayarajan Devannah、Rajgopal Sharma、Donald A. Watson
DOI:10.1021/jacs.9b04175
日期:2019.5.29
A general catalytic method for asymmetric C-alkylation of nitroalkanes using nickel catalysis is described. This method enables the formation of highly enantioenriched β-nitroamides from readily available α-bromoamides using mild reaction conditions that are compatible with a wide range of functional groups. When combined with subsequent reactions, this method allows access to highly enantioenriched