两个亲电子试剂之间的交叉亲电子试剂偶联是在化学计量外部还原剂存在下生成 CC 键的有效且经济的方法。在此,我们报告了一种通过可见光光氧化还原催化实现第一个无外部还原剂的交叉亲电子偶联的新策略。各种带有伯、仲和叔 CN 键的四烷基铵盐与醛/酮和 CO2 进行选择性偶联。值得注意的是,原位生成的副产物三甲胺被有效地用作电子供体。此外,该协议表现出温和的反应条件、低催化剂负载、广泛的底物范围、良好的官能团耐受性和容易的可扩展性。机理研究表明,苄基自由基和阴离子可能是通过光催化产生的关键中间体,
Pd-Catalyzed Suzuki coupling reactions of aryl halides containing basic nitrogen centers with arylboronic acids in water in the absence of added base
作者:Zhao Li、Carol Gelbaum、Zachary S. Campbell、Paul C. Gould、Jason S. Fisk、Bruce Holden、Arvind Jaganathan、Gregory T. Whiteker、Pamela Pollet、Charles L. Liotta
DOI:10.1039/c7nj03567e
日期:——
The Pd-catalyzed Suzuki coupling reactions of a series of aryl chlorides and aryl bromides containing basic nitrogen centers with arylboronicacids in water in the absence of added base are reported. The reactions proceed either partially or entirely under acidic conditions. After surveying twenty-two phosphorus ligands, high yields of products were obtained with aryl chlorides only when a bulky ligand
The TiCl4-catalyzed reaction of aromatic carbonyl compounds with (dialkylamino)dimethylsilanes gave tertiary amines in moderate to high yields. The reductive amination of aliphatic aldehydes was effectively catalyzed by ZnI2. Methyl N-(dimethylsilyl)carbamate as well could be used for reductive amination of carbonyl compounds in the presence of Ph3CClO4.
Simple Metal-Free Direct Reductive Amination Using Hydrosilatrane to Form Secondary and Tertiary Amines
作者:Sami E. Varjosaari、Vladislav Skrypai、Paolo Suating、Joseph J. M. Hurley、Ashley M. De Lio、Thomas M. Gilbert、Marc J. Adler
DOI:10.1002/adsc.201700079
日期:2017.6.6
This work describes the use of cheap, safe, and easy-to-handle hydrosilatrane as the reductant in direct reductive amination reactions. This efficient method enables a facile, metal-free access to secondary and tertiaryaminesfrom a wide range of aldehydes and ketones, with the synthesis of tertiaryamines requiring no additives at all. This reaction demonstrates excellent functional group tolerance
Consecutive β,β′‐Selective C(sp
<sup>3</sup>
)−H Silylation of Tertiary Amines with Dihydrosilanes Catalyzed by B(C
<sub>6</sub>
F
<sub>5</sub>
)
<sub>3</sub>
the two‐fold C(sp3)−H silylation of various trialkylamine derivatives with dihydrosilanes, furnishing the corresponding 4‐silapiperidines in decent yields. The multi‐step reaction cascade involves amine‐to‐enamine dehydrogenation at two alkyl residues and two electrophilic silylation reactions of those enamines, one inter‐ and one intramolecular.
Aqueous Suzuki Coupling Reactions of Basic Nitrogen-Containing Substrates in the Absence of Added Base and Ligand: Observation of High Yields under Acidic Conditions
作者:Zhao Li、Carol Gelbaum、Jason S. Fisk、Bruce Holden、Arvind Jaganathan、Gregory T. Whiteker、Pamela Pollet、Charles L. Liotta
DOI:10.1021/acs.joc.6b01683
日期:2016.9.16
In the former series, the pH of the aqueous phase changed from basic to acidic during the course of the reaction, while in the latter series the aqueous phase was on the acidic side of the pH scale throughout the entire course of reaction. A mechanistic interpretation for these observations, which generally preserves the oxo palladium catalytic cycle widely accepted in the literature, is presented.