Selective Catalytic Synthesis of Unsymmetrical Ethers from the Dehydrative Etherification of Two Different Alcohols
作者:Junghwa Kim、Dong-Hwan Lee、Nishantha Kalutharage、Chae S. Yi
DOI:10.1021/cs5012537
日期:2014.11.7
The cationic ruthenium–hydride complex [(C6H6)(PCy3)(CO)RuH]+BF4– catalyzes selective etherification of two different alcohols to form unsymmetrically substituted ethers. The catalytic method exhibits a broad substrate scope while tolerating a range of heteroatom functional groups in forming unsymmetrical ethers, and it is successfully used to directly synthesize a number of highly functionalized chiral
阳离子钌-氢化物配合物[(C 6 H ^ 6)(PCY 3)(CO)期RuH] + BF 4 -催化两个不同的醇的醚化的选择性,以形成不对称取代的醚。该催化方法在形成不对称醚时可容忍一定范围的杂原子官能团,因此具有广阔的底物范围,并且已成功用于直接合成许多高度官能化的手性非外消旋醚。
An Efficient Means for Generating <i>p</i>-Methoxybenzyl (PMB) Ethers under Mildly Acidic Conditions
作者:Leo Paquette、Catherine Stewart、Xiaowen Peng
DOI:10.1055/s-2008-1032132
日期:2008.2
The protection of a wide variety of alcohols as their p-methoxybenzyl ethers can be performed with PMBO-lepidine in the presence of methyl tosylate or, preferably, camphorsulfonic acid. No inorganic promoters are required, thereby facilitating workup and product isolation.
Synthesis of para-methoxybenzyl (PMB) ethers under neutral conditions
作者:Ernest O. Nwoye、Gregory B. Dudley
DOI:10.1039/b617926f
日期:——
2-(4-Methoxybenzyloxy)-4-methylquinoline reacts with methyl triflate in the presence of alcohols to generate a neutral organic salt that transfers the para-methoxybenzyl (PMB) protecting group onto alcohols in high yield and under mild conditions.
convenient and high yielding approach for the deprotection and scavenging of the p-methoxybenzyl (PMB) group in PMB ethers and PMB esters was developed using POCl3 as the reagent. 4-Methoxybenzyl chloride, a starting material used for the preparation of PMB ethers and esters was regenerated in the deprotection step. This mild and selective procedure tolerates several acid sensitive functional groups.
Abstract PMB ethers of alcohols are obtained in good yields and under mild conditions using the 4-methoxybenzyl N-allyl thiocarbamate and N-bromosuccinimide (NBS)/TfOH as the catalyst. The present method is very fast, simple, and efficient. GRAPHICAL ABSTRACT