α-烷基腈和α-烯烃腈在有机合成和药物化学中非常重要。然而,不同类型的催化剂用于通过借氢实现腈的α-烷基化或通过脱氢偶联方法实现α-烯烃化。设计和开发高性能的地球丰富的催化剂,可以从相同的起始材料中获得不同的产品仍然是一个巨大的挑战。在此,我们报告了一种铁 (0) 催化剂系统,该系统通过简单地改变碱基来实现借氢和脱氢偶联方案之间的化学选择性。广泛的腈类和醇类,包括苄醇、直链脂肪醇、脂环醇、杂环醇和烯丙醇,被选择性且有效地转化为相应的产物。机理研究表明反应机理通过脱氢途径进行。这种铁催化方案对环境无害且原子效率高,可释放 H2和 H 2 O 作为绿色副产物。
Switchable Cobalt-Catalyzed α-Olefination and α-Alkylation of Nitriles with Primary Alcohols
作者:Keshav Paudel、Shi Xu、Keying Ding
DOI:10.1021/acs.orglett.1c01553
日期:2021.7.2
The first switchable α-olefination and α-alkylation of nitriles with primary alcohols catalyzed by a well-defined base transition-metal Co complex was presented. A broad variety of nitriles and primary alcohols are selectively and efficiently converted to the corresponding products by this method. It is noteworthy that the transformation is environmentally benign and atom efficient with H2 and H2O
首次提出了在明确的碱性过渡金属 Co 配合物催化下,腈与伯醇的可切换 α-烯化和 α-烷基化。通过这种方法,多种腈和伯醇被选择性地、高效地转化为相应的产物。值得注意的是,该转化对环境无害且原子效率高,H 2和 H 2 O 是唯一的副产物。
Preparation of Optically Pure Tertiary Phosphine Oxides via the Addition of<i>P</i>-Stereogenic Secondary Phosphine Oxide to Activated Alkenes
Functionalized P,C-stereogenic tertiary phosphineoxides were prepared by the addition of (RP)-menthyl phenylphosphine oxide to activated olefins, in high drP and drC, and were isolated in excellent yields. The reaction was readily catalyzed by Ca(OH)2 or occurred with gentle heating. A wide range of substrates, including vinyl ketones, esters, nitriles, and nitro alkenes, can be used in the reaction
Formerly unknown 3-chloro-4,5-diaryl-1-methylpyrazoles have been prepared through two different synthesis pathways, one of which starts from 2,3-diarylacrylonitriles, the second from 3,3-dichloro-1,2-diarylpropenones. Both approaches rely on the cyclocondensation of diarylated three-carbon synthons with hydrazine derivatives and possess some unique features. One route uses a cyclization reaction, during which a chlorine atom is directly installed at the pyrazole ring that normally would be introduced in subsequent halogenation steps. The second pathway applies the Sandmeyer reaction to introduce this chloro substituent; an approach that is rarely described at the pyrazole nucleus. The obtained tetrasubstituted pyrazoles are isosteres of highly active imidazole fungicides and show good control of Uncinula necator (grape powdery mildew).
Reduction and Benzylation by Means of Benzyl Alcohol. V. A New Synthesis of α,β-Diarylpropionic Acids and the Corresponding Nitriles<sup>1</sup>