Visible-Light-Mediated Regioselective Chlorosulfonylation of Alkenes and Alkynes: Introducing the Cu(II) Complex [Cu(dap)Cl<sub>2</sub>] to Photochemical ATRA Reactions
photocatalyzed protocol utilizing copper–phenanthroline-based catalysts has been developed that can convert a large number of olefins into their chlorosulfonylated products. Besides the Cu(I) complex [Cu(dap)2]Cl, now well-established in photo-ATRA processes, the corresponding Cu(II) complex [Cu(dap)Cl2] proved to be often even more efficient in the title reaction, being advantageous from an economic point of view
已经开发出一种利用铜-菲咯啉基催化剂的可见光介导的光催化方案,该方案可以将大量烯烃转化为其氯磺酰化产物。除了现在在光ATRA工艺中已经确立的Cu(I)络合物[Cu(dap)2 ] Cl之外,相应的Cu(II)络合物[Cu(dap)Cl 2 ]常常在光催化ATRA工艺中更有效。标题反应,从经济角度来看是有利的,但也为光氧化还原催化开辟了新途径。此外,由于它们通过内球机理稳定或与瞬态自由基相互作用的能力,铜配合物的性能优于常用的钌,铱或有机染料基光催化剂。化学计量的Na 2 CO 3的使用与不需要添加剂的活性烯烃相反,发现与铜光催化剂组合使用对将未活性烯烃转化为所需产物是必不可少的。如适当的对照实验所建议的,Na 2 CO 3的作用归因于防止催化剂中毒。
Modular synthesis of (<i>E</i>)-cinnamaldehydes directly from allylarenes <i>via</i> a metal-free DDQ-mediated oxidative process
An efficient synthesis of (E)-cinnamaldehydes by a metal-free DDQ-mediated oxidative transformation of allylarenes was developed. The protocol provides a practical method to prepare diverse (E)-cinnamaldehydes with broad functional group tolerance in good to excellent yields, including easy access to natural products randainal and geranyloxy sinapyl aldehyde from plant extracts. Finally, the mechanism
vinyl arenes with trimethylsilylazide and molecular oxygen as stoichiometric oxidant was achieved. In contrast to photocatalysts based on iridium, ruthenium, or organic dyes, [Cu(dap)2]Cl or [Cu(dap)Cl2] were found to be unique for this transformation, which is attributed to their ability to interact with the substrates through ligand exchange and rebound mechanisms. CuII is proposed as the catalytically
用三甲基甲硅烷基叠氮化物和分子氧作为化学计量氧化剂实现了乙烯基芳烃的可见光加速氧化叠氮化。与基于铱,钌或有机染料的光催化剂相反,发现[Cu(dap)2 ] Cl或[Cu(dap)Cl 2 ]对于这种转化是独特的,这归因于它们与金属,金属或金属的相互作用。底物通过配体交换和反弹机制。有人建议将铜II作为催化活性物质,将其与叠氮化物配位后将进行光加速均质分解,从而形成铜I和叠氮化物自由基。这种激活原则(CU II -X→铜我+ X 。)开启了铜基光催化的新途径。
A Highly Effective (Triphenyl phosphite)palladium Catalyst for a Cross?Coupling Reaction of Allylic Alcohols with Organoboronic Acids
The Catalytic Asymmetric Intermolecular Prins Reaction
作者:C. David Díaz-Oviedo、Rajat Maji、Benjamin List
DOI:10.1021/jacs.1c10245
日期:2021.12.15
Despite their significant potential, catalytic asymmetric reactions of olefins with formaldehyde are rare and metal-free approaches have not been previously disclosed. Here we describe an enantioselective intermolecular Prins reaction of styrenes and paraformaldehyde to form 1,3-dioxanes, using confined imino-imidodiphosphate (iIDP) Brønsted acid catalysts. Isotope labeling experiments and computations
尽管它们具有巨大的潜力,但烯烃与甲醛的催化不对称反应是罕见的,并且以前没有公开过不含金属的方法。在这里,我们描述了苯乙烯和多聚甲醛的对映选择性分子间 Prins 反应以形成 1,3-二恶烷,使用受限的亚氨基-亚氨基二磷酸 ( i IDP) 布朗斯台德酸催化剂。同位素标记实验和计算表明酸活化甲醛低聚物向烯烃中的协同、高度异步添加。对映体富集的 1,3-二恶烷可以转化为相应的光学活性 1,3-二醇,它们是有价值的合成构件。