Olefins are prevalent substrates and functionalities. The synthesis of olefins from readily available starting materials such as alcohols, amines and carboxylic acids is of great significance to address the sustainability concerns in organic synthesis. Metallaphotoredox-catalyzed defunctionalizations were reported to achieve such transformations under mild conditions. However, all these valuable strategies
Superelectrophilic Fe(III)–Ion Pairs as Stronger Lewis Acid Catalysts for (<i>E</i>)-Selective Intermolecular Carbonyl–Olefin Metathesis
作者:Haley Albright、Hannah L. Vonesh、Corinna S. Schindler
DOI:10.1021/acs.orglett.0c00917
日期:2020.4.17
intermolecular carbonyl–olefin metathesis reaction is described that relies on superelectrophilic Fe(III)-based ionpairs as stronger Lewis acid catalysts. This new catalytic system enables selective access to (E)-olefins as carbonyl–olefin metathesis products. Mechanistic investigations suggest the regioselective formation and stereospecific fragmentation of intermediate oxetanes to be the origin of this
描述了一种分子间羰基-烯烃复分解反应,该反应依赖于超亲电 Fe(III) 基离子对作为更强的路易斯酸催化剂。这种新的催化系统能够选择性地使用 ( E )-烯烃作为羰基-烯烃复分解产物。机理研究表明,中间体氧杂环丁烷的区域选择性形成和立体特异性断裂是这种选择性的来源。优化的条件适用于各种芳基醛和三取代烯烃,并在 28 个示例中得到证明,总产率高达 64%。
Development of a polymer bound Wittig reaction and use in multi-step organic synthesis for the overall conversion of alcohols to β-hydroxyamines
作者:Martin H. Bolli、Steven V. Ley
DOI:10.1039/a803612h
日期:——
An efficient combinatorial access to β-hydroxyamines suitable for automation is achieved by the mild oxidation of alcohols to aldehydes by polymer supported perruthenate (PSP), the subsequent clean olefination of the obtained aldehydes by polymer supported Wittig reagents followed by the epoxidation of the olefins by dimethyldioxirane (DMDO), and the final aminolysis of the epoxides with various amines is described.
A novel biocatalytic oxidativealkenecleavage activity was identified in protein TM1459 from Thermotoga maritima, a so far uncharacterised metalloprotein with a cupin fold, which preferentially binds manganese (over iron and zinc). Various styrene derivatives were converted with high chemoselectivity to the corresponding carbonyl compounds by the manganese-containing protein, using organic hydroperoxide
cross‐metathesis is described. Photoinduced hole catalysis was used to promote the formation of 1,3‐diols from aldehydes and styrenes, which were then readily fragmented under acidic conditions to form the cross‐metathesis products. The use of 1,3‐diols as intermediates, rather than the energetically more demanding oxetanes, provides a new, orthogonal mechanistic strategy for carbonyl–olefin cross‐metathesis.