The first nickel-catalyzed desymmetric hydrogenation has been achieved. With the Ni(OTf)2/(S,S)-Ph-BPE system, a series of γ,γ-disubstituted cyclohexadienones were transformed to the corresponding cyclohexenones with a chiral all-carbon quaternary center at the γ position in high yields (92% to 98%) and excellent enantioselectivities (92% to 99% ee). This catalytic system can also tolerate the desymmetric
首次实现了镍催化的不对称氢化。使用 Ni(OTf)2/(S,S)-Ph-BPE 系统,一系列 γ,γ-二取代环己二烯酮以高产率转化为相应的环己烯酮,其在 γ 位具有手性全碳四元中心( 92% 至 98%)和出色的对映选择性(92% 至 99% ee)。该催化体系还可以耐受螺碳环环己二烯酮的去对称反应,以产生相应的带有手性螺季碳的环己烯酮,收率高(94% 至 98%)和 ee 值(96% 至 99% ee)。此外,该方法为天然产物大麻吡酮 A 和 B 的中间体提供了一种高效、简洁的合成路线。
Asymmetric Synthesis of Remote Quaternary Centers by Copper-Catalyzed Desymmetrization: An Enantioselective Total Synthesis of (+)-Mesembrine
作者:Apparao Bokka、James X. Mao、John Hartung、Steven R. Martinez、Justin A. Simanis、Kwangho Nam、Junha Jeon、Xiaoqiang Shen
DOI:10.1021/acs.orglett.8b02084
日期:2018.9.7
Catalytic asymmetric syntheses of remote quaternary stereocenters have been developed by copper-catalyzed 1,4-hydrosilylation of γ,γ-disubstituted cyclohexadienones. A variety of cyclohexenones have been synthesized in good yield and excellent enantioselectivity. Versatile 2-silyloxy diene intermediates bearing γ,γ-disubstituted all carbon stereogenic centers can be isolated from the mild reaction
the corresponding cyclohexenones 4 with a remote chiral all‐carbon quaternary center at the γ position is described. Chiral rhodium–bis(oxazolinyl)phenyl complexes 1 were effective catalysts for this transformation. This catalytic system was extended to the asymmetric transformation of spirocarbocyclic cyclohexadienones 5 to give the corresponding products 6 with highenantiomeric ratios.
Rhodium-Catalyzed Desymmetric Arylation of <i>γ,γ</i>-Disubsituted Cyclohexadienones: Asymmetric Synthesis of Chiral All-Carbon Quaternary Centers
作者:Yu Qiao、Shiming Bai、Xiao-Feng Wu、Ying Yang、He Meng、Jialin Ming
DOI:10.1021/acs.orglett.2c00225
日期:2022.2.25
desymmetric arylation of prochiral cyclohexadienones with ArZnCl in the presence of an (R)-segphos–rhodium catalyst gave high yields of the corresponding cyclohexenones, which contain a chiral arylated carbon center at the β-position and a chiral all-carbon quaternary center at the γ-position, with high diastereo- and enantioselectivities. This catalytic system was also applied to the arylation of spirocarbocyclic
在 ( R )-segphos-铑催化剂存在下,前手性环己二烯酮与 ArZnCl 的不对称芳基化得到高产率的相应环己烯酮,其在β位含有手性芳基化碳中心,在γ-位,具有高非对映选择性和对映选择性。该催化体系还应用于螺碳环环己二烯酮的芳基化,并提供了相应的带有高 dr 和 ee 的手性螺季碳的环己烯酮。
Ring‐Opening Amino Esterification of Cyclic Ketones to Access Distal Amino Acid Derivatives
作者:Ishin Tomiya、Yuhao Wu、Kengo Hyodo
DOI:10.1002/adsc.202301421
日期:2024.4.9
synthesizing distal aminoacidderivatives by the ring-opening reaction of cyclic ketones, following the amino esterification functionalization of both terminals. To achieve this goal, we performed the ring-opening reaction of cyclic ketones with an aminating reagent and alcohol under metal- and photocatalysis-free conditions in a single step. The method directly afforded distal aminoacidderivatives bearing