首次开发了膦催化的 2-(4 H-苯并[ d ][1,3]恶嗪-4-基)丙烯酸酯与异氰酸酯的对映选择性形式 (4 + 2)-环加成反应。手性膦有机催化剂对 2-(4 H-苯并[ d ][1,3]oxazin-4-yl) 丙烯酸酯的初始 S N 2' 攻击产生了关键的含膦偶极中间体,随后与异氰酸酯以 60-84% 的收率和 61-92% 的 ee 提供范围广泛的 3,4-二氢喹唑啉-2-酮。
Cp*Co(III)‐Catalyzed
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‐Amidation of Benzaldehydes with Dioxazolones Using Transient Directing Group Strategy
作者:Bhuttu Khan、Vikas Dwivedi、Basker Sundararaju
DOI:10.1002/adsc.201901267
日期:2020.3.4
metal‐catalyzed ortho‐selective C(sp2)−H amidation of weakly coordinating aldehydes remains limited to precious metals such as Ir, Rh, Ru, etc. Herein, we put forward a novel report on ortho‐amidation of benzaldehydes employing user‐friendly dioxazolones under cost‐effective and air‐stable Cp*Co(III) catalysis. This catalytic transformation involves transient directing group strategy to enhance the ligating
Rh(III)-Catalyzed ortho-C–H amidation of ketones and aldehydes under cooperative metal organocatalysis has been utilized for synthesizing various ortho-amidocarbonyl analogs, and the reaction for the aldehyde proceeds at ambient temperature. The aniline derivative 3,5-bis(trifluoromethyl)aniline promotes the amidation reaction via a transient imine directing group. The efficient amidation agent is
Rh-catalyzed Transient Directing Group Promoted C-H Amidation of Benzaldehydes Utilizing Dioxazolones
作者:Xiaoyang Wang、Song Song、Ning Jiao
DOI:10.1002/cjoc.201700726
日期:2018.3
Transition‐metal catalyzedC—H functionalization of benzaldehydes is of great interest in organic synthesis. Herein, we developed a transient directing group assisted amidation of benzaldehydes catalyzed by rhodium catalyst. With the employment of 10 mol% of 4‐trifluoromethyl aniline, the in situ generated imine groups as the directing group efficiently enable this transformation. By using this protocol
Rh<sup>III</sup>-Catalyzed site-selective amidation with nitrone as a traceless directing group: an approach to functionalized arylaldehydes
作者:Hong Deng、Hongji Li、Wenge Zhang、Lei Wang
DOI:10.1039/c7cc05297a
日期:——
An efficient Rh-catalyzed site-selective amidation of nitrones with 1,4,2-dioxazol-5-ones has been developed. The reaction can tolerate a number of groups and generates functionalized aldehydes in good yields. The significance of the amidation is highlighted by the late-stage transformation of the formed aldehydes.
One‐Pot Divergent Synthesis of Benzoxazines and Dihydroquinolines from Morita‐Baylis‐Hillman Alcohols
作者:Tao Wang、Xuling Chen、Pengfei Li
DOI:10.1002/ejoc.202200767
日期:2022.8.12
Catalyst-controlled reactions of MBH alcohols were established. DABCO enables the synthesis of 4H-benzo[d][1,3]oxazines while Bu4NBr/NaOH leads to the formation of 1,2-dihydroquinolines.