光氧化还原和极性反转催化的协同组合使硅烷与 H 2的析氢交叉偶联成为可能O、醇、酚和硅烷醇,它们分别以中等至极好的收率提供相应的硅烷醇、单甲硅烷基醚和二甲硅烷基醚。在仅存在有机光催化剂 4-CzIPN 和硫醇 HAT 催化剂的情况下,Si-H 和 O-H 的脱氢交叉偶联顺利进行,底物范围广,官能团相容性好,不需要任何金属、外部氧化剂和质子还原剂,这与之前报道的光催化析氢交叉偶联反应不同,后者通常需要质子还原助催化剂,如钴络合物。从机制上讲,生成甲硅烷基阳离子中间体以促进交叉偶联反应,因此代表了一种前所未有的生成甲硅烷基阳离子的方法通过可见光光氧化还原催化。
An efficient method for the dehydrogenative coupling of silanes with alcohols under photocatalysis was developed. The reaction proceeded in the presence of Ru(bpy)3Cl2 (0.5 mol%) under visible light irradiation in acetonitrile at room temperature. The developed methodology was also applicable for the synthesis of silanols using water as a coupling partner.
Alkynylsilanes – a missing piece of different silylation agents, can serve as valuable substrates in the O‐silylation through a dealkynative coupling with alcohols or silanols. The described approach displays a whole array of advantages in terms of green chemistry and is a promising alternative to existing methodologies.
Palladium-Catalyzed Cross-Coupling Reactions of Substituted Aryl(dimethyl)silanols
作者:Scott E. Denmark、Michael H. Ober
DOI:10.1002/adsc.200404204
日期:2004.12
cross-coupling of aryl(dimethyl)silanols with substituted aryl halides. Extensive optimization studies led to the identification of key variables (solvent, catalyst, additive, and hydration level) that influence the rate and selectivity of the process. Manipulation of these factors provides an effective coupling method of wide scope and generality. Electron-rich aryl(dimethyl)silanols undergo cross-coupling
oxidation of organosilanes to silanols with H2O2 under neutral reaction conditions has been accomplished. A variety of organosilanes with alkyl, aryl, alknyl, and heterocyclic substituents were tolerated, as well as sterically hindered organosilanes. The oxidation appears to proceed by a concerted process involving a manganese hydroperoxide species. Featuring mild reaction conditions, fast oxidation,
在中性反应条件下,用H 2 O 2进行的第一次锰催化的有机硅烷氧化为硅烷醇。可以耐受具有烷基,芳基,炔基和杂环取代基的多种有机硅烷,以及受阻位有机硅烷。氧化似乎是通过涉及氢过氧化锰物质的协同过程进行的。该方案具有温和的反应条件,快速的氧化作用,并且没有废副产物,可实现硅烷醇和硅烷二醇的低成本,生态友好的合成。
Selective Electrochemical Hydrolysis of Hydrosilanes to Silanols via Anodically Generated Silyl Cations
The first electrochemical hydrolysis of hydrosilanes to silanols under mild and neutral reaction conditions is reported. The practical protocol employs commercially available and cheap NHPI as a hydrogen‐atom transfer (HAT) mediator and operates at room temperature with high selectivity, leading to various valuable silanols in moderate to good yields. Notably, this electrochemical method exhibits a