Synthetic Versatility of Lipases: Application for Si–O Bond
Formation and Cleavage
作者:Patrícia Brondani、Mateus Mittersteiner、Morgana Voigt、Bruna Klinkowski、Dilamara Riva Scharf、Paulo de Jesus
DOI:10.1055/s-0037-1610281
日期:2019.1
Abstract Several commercially available lipases were examined in a study on O–Si bond formation and cleavage applying silicon-based protecting groups and alcohols or the corresponding silylethers. With regard to deprotection, from silylether to the corresponding alcohol, only the solvent and the lipase were necessary. The influence of the protecting group, the lipase source, and the substituent was
Iron-catalysed alkene hydrogenation and reductive cross-coupling using a bench-stable iron(ii) pre-catalyst
作者:Dominik J. Frank、Léa Guiet、Alexander Käslin、Elliot Murphy、Stephen P. Thomas
DOI:10.1039/c3ra44519d
日期:——
Operationally simple, iron-catalysed hydrogenation and reductive cross-coupling protocols have been developed using a bench-stableiron(II) pre-catalyst. The hydrogenation of 18 alkenes (50–99%) and reductive cross-coupling of vinyl halides with aryl- and alkyl Grignard reagents (8 examples, 18–99%) is reported using 3 mol% pre-catalyst and hydrogen as stoichiometric reductant (1–50 bar).
Rapid Assessment of Protecting-Group Stability by Using a Robustness Screen
作者:Karl D. Collins、Andreas Rühling、Fabian Lied、Frank Glorius
DOI:10.1002/chem.201304508
日期:2014.3.24
establish the stability of widely utilized silyl, acetal, and carbamateprotectinggroups to a given set of reaction conditions. Assessment of up to twelve protectinggroups in a single experiment has been demonstrated. Evaluation of this protocol in two unrelated synthetic transformations suggests that this method can be used to select appropriate protectinggroups in the design of synthetic routes.
Single-Step Dual Functionalization: One-Pot Bromination-Cross-Dehydrogenative Esterification of Hydroxy Benzaldehydes with CCl3Br – A Comparison with Selectfluor
作者:Ranadeep Talukdar
DOI:10.1055/s-0037-1610717
日期:2019.9
Bromination of phenolic compounds without directly using molecular bromine possesses much importance. In this article an IrIII/CCl3Br-assisted single-step double functionalization of hydroxy benzaldehydes is reported. It involves simultaneous esterification of the aldehyde group and bromination of the aryl ring of phenolic aldehydes in one-pot. The reaction proceeds under mild conditions in the presence
不直接使用分子溴对酚类化合物进行溴化具有重要意义。本文报道了 IrIII/CCl3Br 辅助的羟基苯甲醛单步双官能化。它涉及在一锅中同时进行醛基酯化和酚醛芳环的溴化。在 445 nm 蓝光 LED 光的存在下,反应在温和条件下进行,以中等至良好的产率获得高度官能化的溴羟基苯甲酸酯。相比之下,Selectfluor 作为氧化剂只产生非溴酚酸酯。
B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>-Catalyzed Chemoselective Defunctionalization of Ether-Containing Primary Alkyl Tosylates with Hydrosilanes
cleavage promoted by B(C6F5)3 /Et3SiH proceeds preferentially with primary tosylates in the presence of primary and secondary silylethers and aryl ethers. This reactivity difference enables the chemoselective defunctionalization of several 1,n‐diols, and the efficiency of the new procedure is highlighted by the selective deoxygenation of the hydroxymethyl group of an orthogonally protected carbohydrate. Tosylates
在伯和仲甲硅烷基醚和芳基醚的存在下,由B(C 6 F 5)3 / Et 3 SiH促进的催化C(sp 3)-O键裂解优先与伯甲苯磺酸盐一起进行。这种反应性的差异使几种1,n-二醇的化学选择性脱官能化,并且正交保护的碳水化合物的羟甲基选择性脱氧突出了新方法的效率。具有邻苯基的甲苯磺酸酯在邻氨基苯甲酸辅助下被裂解。