Selective deprotection of silyl-protected phenols using solid NaOH and a phase transfer catalyst
摘要:
Aryl silyl ethers can be deprotected to yield phenols in good to excellent yields using a biphasic system of 10 equivalents of NaOH and catalytic Bu4NHSO4 in 1,4-dioxane. Alkyl silyl ethers prepared using a variety of silyl protecting groups survive under these conditions, allowing selective deprotection of silyl-protected phenols in the presence of silyl-protected alcohols. (C) 1999 Elsevier Science Ltd. All rights reserved.
Recombinant silicateins as model biocatalysts in organosiloxane chemistry
作者:S. Yasin Tabatabaei Dakhili、Stephanie A. Caslin、Abayomi S. Faponle、Peter Quayle、Sam P. de Visser、Lu Shin Wong
DOI:10.1073/pnas.1613320114
日期:2017.7.3
with a range of model organosilanols and silyl ethers. The enzymes’ kinetic parameters were obtained by a high-throughput colorimetric assay based on the hydrolysis of 4-nitrophenyl silyl ethers. These assays showed unambiguous catalysis with kcat/Km values on the order of 2–50 min−1 μM−1. Condensation reactions were also demonstrated by the generation of silyl ethers from their corresponding silanols
天然海绵中的硅酸盐酶家族(门孔植物)在催化无机二氧化硅结构的形成方面具有独特的性质,该有机二氧化硅可被有机体整合到其骨架中。但是,到目前为止,仍未充分探索由这些酶催化的有机硅氧烷的合成。为了研究这些酶与这一重要类化合物的反应性,使用一系列模型有机硅烷醇和甲硅烷基醚研究了它们对Si–O键水解和缩合的催化作用。通过基于4-硝基苯基甲硅烷基醚的水解的高通量比色测定法获得了酶的动力学参数。这些测定显示出明确的催化作用,k cat / K m值约为2–50分钟-1 μM -1。缩合反应还通过由其相应的硅烷醇和醇生成甲硅烷基醚来证明。值得注意的是,当与同时带有脂肪族和芳香族羟基的底物一起出现时,与非酶甲硅烷基化形成鲜明对比的是,该酶优先使后者基团甲硅烷基化。此外,硅酸酯类能够催化转醚化,其中来自一种甲硅烷基醚的甲硅烷基可以转移到受体醇上。尽管与蛋白酶组织蛋白酶L具有紧密的序列同源性,但是当针对相似的底
Silyl methallylsulfinates: efficient and powerful agents for the chemoselective silylation of alcohols, polyols, phenols and carboxylic acids
Alcohols, phenols and carboxylic acids are silylated with very good yields in the presence of silyl methallylsulfinates under non-basic conditions and with the formation of volatile co-products.
We have developed a unique approach for the thermally promoted cycloaddition of cyclohexadienone-tethered allenes to form a versatile cyclobutane-fused oxygen-containing tricyclic framework in an environmentally friendly and atomic economic fashion with high regioselectivity. The reaction encompasses a broad substrate scope and functional group tolerance of cyclohexadienone moieties. Moreover, the
Selective deprotection of silyl-protected phenols using solid NaOH and a phase transfer catalyst
作者:R.David Crouch、Mike Stieff、Jessica L. Frie、Amy B. Cadwallader、Daniel C. Bevis
DOI:10.1016/s0040-4039(99)00459-1
日期:1999.4
Aryl silyl ethers can be deprotected to yield phenols in good to excellent yields using a biphasic system of 10 equivalents of NaOH and catalytic Bu4NHSO4 in 1,4-dioxane. Alkyl silyl ethers prepared using a variety of silyl protecting groups survive under these conditions, allowing selective deprotection of silyl-protected phenols in the presence of silyl-protected alcohols. (C) 1999 Elsevier Science Ltd. All rights reserved.