Cupric sulfate pentahydrate (CuSO4·5H2O): a mild and efficient catalyst for tetrahydropyranylation/depyranylation of alcohols and phenols
作者:Abu T. Khan、Lokman H. Choudhury、Subrata Ghosh
DOI:10.1016/j.tetlet.2004.08.141
日期:2004.10
Various alcohols and phenols can be smoothly converted to the corresponding THP ethers using 20 mol % CuSO4·5H2O under mild reaction conditions at room temperature. Some of the major advantages of this procedure are nonaqueous work-up, very good yields, less expensive catalyst and compatibility with other protecting groups.
Silica-Supported Perchloric Acid (HClO<sub>4</sub>-SiO<sub>2</sub>): A Versatile Catalyst for Tetrahydropyranylation, Oxathioacetalization and Thioacetalization
作者:Abu Khan、Tasneem Parvin、Lokman Choudhury
DOI:10.1055/s-2006-942465
日期:2006.8
A simple and convenient syntheticprotocol for the protection of hydroxyl group as tetrahydropyranyl ether as well as carbonyl functionality as oxathioacetal and thioacetal has been achieved using a catalytic amount of silica-supported perchloric acid undersolvent-freeconditions. This protocol has many advantages compared to currently available methodologies in terms of simplicity, yield, reaction
Alcohols were acetylated or formylated with triphenylphosphine and carbon tetrabromide in ethylacetate or ethyl (or methyl) formate at room temperature. THP or TBDMS ether of primary alcohol got converted into formate or acetate under the experimental conditions employed in one pot operation.
Solvent-free tetrahydropyranylation of alcohols catalyzed by amine methanesulfonates
作者:Rui Wang、MingZhu Sun、Heng Jiang
DOI:10.1007/s11164-010-0222-6
日期:2011.1
A comparative study of tetrahydropyranylation of alcohols under various solvents or solvent-free conditions using different amine methanesulfonates as catalysts shows that tetrahydropyranyl ethers of alcohols are obtained under solvent-free conditions in good yields using catalytic amounts of triethylenediamine methanesulfonate, 1,6-hexanediamine methanesulfonate, diethylenetriamine methanesulfonate and pyridine methanesulfonate, respectively. The reaction occurs readily in short times at room temperature catalyzed by these catalysts, especially triethylenediamine methanesulfonate. Some of the major advantages of this procedure are that the catalysts are environmentally friendly, highly effective, and easy to prepare and handle. The reaction is also clean and needs no solvent, and the work-up is very simple.
Efficient acidic functionalization of mesoporous silica LUS-1 (Laval University Silica) and its application as a recyclable heterogeneous catalyst for DHP (3,4-dihydro-2H-pyran) protection of alcohols and the subsequent removal of the corresponding protecting group have been reported. This green method offers a number of advantages such as short reaction time, good yields of protection and deprotection
介孔二氧化硅LUS-1(Laval University Silica)的有效酸性官能化及其作为DHP(3,4-dihydro-2 H -pyran)醇保护和随后去除相应保护基的可循环均相催化剂的应用报告。这种绿色方法具有许多优点,例如反应时间短,保护和脱保护的收率高,后处理步骤简单,可循环使用的催化剂以及环境友好的条件。