Chemoselective O-tert-butoxycarbonylation of phenols using 6,7-dimethoxyisoquinoline as a novel organocatalyst
作者:Yukako Saito、Yuichi Yoshimura、Hiroki Takahata
DOI:10.1016/j.tetlet.2010.10.114
日期:2010.12
The chemoselective O-tert-butoxycarbonylation of phenols using low levels (5-0.1 mol %) of 6,7-dimethoxyisoquinoline as a reusableorganocatalyst is described. (C) 2010 Elsevier Ltd. All rights reserved.
Base-labile tert-butoxycarbonyl (Boc) group on phenols
Phenols are deprotected with weak bases from their tert-butoxycarbonyl (Boc) derivatives. Boc deprotection with bases can avoid side reactions during the deprotection with acids. We note the lability of the Boc to bases and are able to utilize it as a new cleavage condition for synthetic studies. (C) 2003 Elsevier Ltd. All rights reserved.
Mixed metal MgO-ZrO2 nanoparticle-catalyzed O-tert-Boc protection of alcohols and phenols under solvent-free conditions
作者:Manoj B. Gawande、Sharad N. Shelke、Paula S. Branco、Anuj Rathi、Rajesh K. Pandey
DOI:10.1002/aoc.2846
日期:2012.8
method for O‐tert‐Boc protection of alcohols and phenols catalyzed by MgO–ZrO2 nanoparticles under solvent‐free conditions is described. A variety of phenols, alcohols (aliphatic and aromatic) were converted to corresponding O‐tert‐Boc products in good to excellent yield (50–95%). The present protocol is expedient, simple, and efficient under solvent‐free conditions. The MgO–ZrO2 Nps are easily prepared
A new simple and effective method for the formation/cleavage of O-tert-butoxy carbonates of alcohols and phenols is proposed. Mesoporous silica-supported Er(III) (ErIII-MCM-41) was used as an efficient and reusable solid catalyst in the solvent-free ultrasound-assisted synthesis of Boc-carbonate derivatives of a wide range of alcohols and phenols. The fast, selective deprotection of Boc-derivatives is achieved with a very low amount of Er(OTf)3 in ethanol under microwave irradiation. Therefore, the entire protection/de-protection process is very attractive, from the point of view of sustainability.