Selective CS bond cleavage of a β-sultam ring was achieved by the reactions with Lewis acids. Aryl ketones or aldehyde were provided from 3-aryl-β-sultams whereas β-sultams bearing a poorly migratory substituent at C-3 gave trans-1,2,3-oxathiazolidine 2-oxides and/or cis-aziridines. These reactions were influenced by the cation-stabilizing capability of C-4 substituents and by the configuration of
Manganese(III) Porphyrin‐Catalyzed Dehydrogenation of Alcohols to form Imines, Tertiary Amines and Quinolines
作者:Kobra Azizi、Sedigheh Akrami、Robert Madsen
DOI:10.1002/chem.201900737
日期:2019.5.2
Manganese(III) porphyrin chloride complexes have been developed for the first time as catalysts for the acceptorless dehydrogenative coupling of alcohols and amines. The reaction has been applied to the direct synthesis of imines, tertiary amines and quinolines where only hydrogen gas and/or water are formed as the by‐product(s). The mechanism is believed to involve the formation of a manganese(III) alkoxide
作者:Joshua Britton、Jared W. Castle、Gregory A. Weiss、Colin L. Raston
DOI:10.1002/chem.201602373
日期:2016.7.25
continuously fed through a thin‐film reactor where the intermediates accrue molecular complexity as they progress through the flow system. Flow chemistry allows rapid multistep transformations to occur via reaction compartmentalization, an approach not amenable to using conventional flasks. Thin film processing can also access facile in situ solvent exchange to drive reaction efficiency, and through this method
受大自然通过连续合成转化构建复杂分子的能力的启发,α-氨基膦酸盐的流水线合成方法已被开发出来。在这种方法中,简单的起始材料连续地通过薄膜反应器,其中中间体在流过流动系统时会增加分子的复杂性。流动化学允许通过反应区室化进行快速的多步转化,这种方法不适合使用传统的烧瓶。薄膜加工还可以进行方便的原位溶剂交换以提高反应效率,通过这种方法,α-氨基膦酸酯的合成仅需要443 s的停留时间即可产生3.22 g h -1。流水线合成实现了前所未有的反应灵活性和加工效率。
Molybdenum-Catalyzed Dehydrogenative Synthesis of Imines from Alcohols and Amines
作者:Kobra Azizi、Robert Madsen
DOI:10.1002/cctc.201800677
日期:2018.9.7
synthesis of imines from primary alcohols and amines with the liberation of dihydrogen. The catalyst is generated in situ from molybdenum hexacarbonyl, 1,3‐dicyclohexylimidazolium chloride and potassium tert‐butoxide and is further stabilized by the phosphine ligand dppe. Imines are formed in moderate to good isolated yields and a variety of alcohols and amines can be employed in the reaction including anilines
Development and mechanistic investigation of the manganese(<scp>iii</scp>) salen-catalyzed dehydrogenation of alcohols
作者:Simone V. Samuelsen、Carola Santilli、Mårten S. G. Ahlquist、Robert Madsen
DOI:10.1039/c8sc03969k
日期:——
The firstexample of a manganese(III) catalyst for the acceptorless dehydrogenation of alcohols is presented. N,N′-Bis(salicylidene)-1,2-cyclohexanediaminomanganese(III) chloride (2) has been shown to catalyze the directsynthesis of imines from a variety of alcohols and amines with the liberation of hydrogen gas. The mechanism has been investigated experimentally with labelled substrates and theoretically
介绍了用于醇的无受体脱氢的锰 ( III ) 催化剂的第一个例子。N , N' -双(水杨基)-1,2-环己烷二氨基锰 ( III ) 氯化物 ( 2 ) 已被证明可催化从各种醇和胺直接合成亚胺,并释放氢气。该机制已经用标记的底物进行了实验研究,并在理论上用 DFT 计算进行了研究。结果表明金属-配体双功能途径,其中salen配体中的两个亚胺基团首先被还原形成锰(III) 酰胺络合物作为催化活性物质。然后通过逐步的外球氢转移发生醇的脱氢,产生氢化锰( III ),从中释放氢气。