C=C双键与分子氧的氧化裂解产生羰基化合物是化学和药物合成中的一个重要转化。在自然界中,含有第一排过渡金属的酶,特别是血红素和非血红素铁依赖性酶,在环境条件下很容易激活 O 2并以极其精确的方式氧化裂解 C=C 键。然而,该反应对合成化学家来说仍然具有挑战性。只有少数已知的合成金属催化剂允许在 O 2大气压下氧化裂解烯烃,很少有人知道催化未活化烯烃的裂解。在这项工作中,我们描述了一种光驱动、Mn 催化的协议,用于在 1 个大气压的 O 2下将烯烃选择性氧化为羰基化合物。首次使用第一排生物相关金属催化剂,在清洁、温和的条件下,可以将芳香族和各种未活化的脂肪族烯烃氧化成酮和醛。此外,该协议显示出非常好的功能组耐受性。机理研究表明,Mn-oxo 物种,包括不对称的混合价双 (μ-oxo)-Mn(III,IV) 络合物,参与氧化,溶剂甲醇参与 O 2活化,导致oxo 物种的形成。
The first example of the thiyl radical promoted ligand-free iron-catalyzed oxidative cleavage of alkenes using molecular oxygen (1 atm) has been developed. The reaction proceeds under mild reaction conditions with high efficiency and high chemo- and regioselectivity. It features a broad substrate scope and excellent functional group compatibility, enabling facile access to valuable molecules for application
methylenation of acyl fluorides and acyl chlorides with substituted with aryl, alkenyl, and alkyl groups trimethylaluminum afforded an array of 2-substituted propene derivatives. The addition of a catalytic amount of DPPM increased an efficiency of the reactions. Trimethylaluminum as the methylenation reagent not only eliminates the presynthesis of methylene transfer reagent, but provides an efficient method for
Nickel-Phosphine Complex-Catalyzed Grignard Coupling. I. Cross-Coupling of Alkyl, Aryl, and Alkenyl Grignard Reagents with Aryl and Alkenyl Halides: General Scope and Limitations
(s)), aryl, and alkenyl Grignard reagents and nonfused, fused, and substituted aromatic halides and haloolefins. Limitations lie in sluggish reactions between alkyl Grignard reagents and dihaloethylenes. The most effective catalysts are [Ni(C6H5)2P(CH2)3P(C6H5)2}Cl2] for alkyl and simple aryl Grignard reagents, [Ni(CH3)2P(CH2)2P(CH3)2}Cl2] for alkenyl and allylic Grignard reagents and [NiP(C6H5)3}2-Cl2]
已经确定,二卤代二膦镍 (II) 配合物对格氏试剂与芳基和链烯基卤化物的选择性交叉偶联表现出极高的催化活性。由于该催化反应程序简单、反应条件温和、偶联产物的收率和纯度高,以及广泛适用于涉及伯和仲烷基的反应(无论β-的存在与否),该催化反应可用于合成实践。氢 (s))、芳基和烯基格氏试剂以及非稠合、稠合和取代的芳族卤化物和卤代烯烃。限制在于烷基格氏试剂和二卤乙烯之间的缓慢反应。对于烷基和简单的芳基格氏试剂,最有效的催化剂是 [Ni(C6H5)2P(CH2)3P(C6H5)2}Cl2],[Ni(CH3)2P(CH2)2P(CH3)2}Cl2] 用于烯基和烯丙基格氏试剂,[NiP(C6H5)3}2-Cl2] 用于空间位阻芳基格氏试剂和卤化物。膦配体对...的巨大稳定作用
Photoinduced [3+2] Annulation of Alkene with o-Iodoanilines: An Expedient Approach to Indolines
作者:Wujiong Xia、Xinxin Zhao、Lin Guo、Chao Yang
DOI:10.1055/s-0040-1705963
日期:2021.4
A highly regioselective [3+2] cyclization of alkenes with 2-iodoanilines under the irradiation of UV light is described. This general, metal-free strategy facilitates the direct preparation of 2-mono-/disubstituted indolines as well as spiroindolines through alkene carboamination in one step. Mechanistic studies suggested that the photochemical protocol proceeded via a radical pathway.
Nickel catalyzed cross-coupling of modified alkyl and alkenyl Grignard reagents with aryl- and heteroaryl nitriles: activation of the CCN bond
作者:Joseph A Miller、John W Dankwardt
DOI:10.1016/s0040-4039(03)00075-3
日期:2003.2
The nickelcatalyzed cross-coupling of alkyl and alkenyl Grignard reagents with arylnitrile derivatives affords good yields of the corresponding aryl alkanes or aryl alkenes via activation of the CCN bond. To prevent direct addition of the nucleophile to the nitrile group, the reactivity of the Grignard reagent was modulated by reaction with either LiOt-Bu or PhSLi prior to cross-coupling. The optimum