A simple and efficient alkylation of aromatic and heteroaromatic compounds via the direct SN1-type nucleophilic substitution of benzylic alcohols in the presence of catalytic amounts of the strong Brønsted acid o-benzenedisulfonimide under neat conditions is herein reported. A library of di- and triaryl (and heteroaryl) methanes was prepared in good yields and high regioselectivity. The observed reactivity
本文报道了在纯净条件下,在催化量的强布朗斯台德酸邻苯二磺酰亚胺存在下,通过苄基醇的直接S N 1型亲核取代,对芳香族和杂芳香族化合物进行的简单有效烷基化。以高收率和高区域选择性制备了二芳基和三芳基(和杂芳基)甲烷的库。已证明观察到的反应性与Mayr的亲核性和亲电子性等级相符。
Surfactant-Type Brønsted Acid Catalyzed Dehydrative Nucleophilic Substitutions of Alcohols in Water
作者:Seiji Shirakawa、Shū Kobayashi
DOI:10.1021/ol062813j
日期:2007.1.1
A protocol for the dehydrative nucleophilicsubstitution of benzyl alcohols with a variety of carbon- and heteroatom-centered nucleophiles using dodecylbenzenesulfonic acid (DBSA) as a surfactant-type Bronsted acid catalyst in water has been developed. The reaction system can be applied to the stereoselective C-glycosylation of 1-hydroxy sugars in water. [reaction: see text].
Kinetic analysis was used as a tool for rational optimization of a catalytic, direct substitution of alcohols to enable the selective formation of unsymmetrical ethers, thioethers, and Friedel–Crafts alkylation products using a moisture-tolerant and commercially available zirconium complex (2 to 8 mol%). Operating in air and in the absence of dehydration techniques, the protocol furnished a variety
In high-temperature water a series of benzyl and allylic alcohols reacted with 1,3-dicarbonyl compounds and activated aromatic compounds to give the alkylated products without added catalysts.
An efficient Br2-catalyzed synthesis of α-(3-indolyl) ketones via dehydrative coupling of simple indoles with acyloins is presented. This reaction proceeded with high C-3 selectivity and a wide substrate scope, and without any metal catalyst. Both the activation of alcohols by carbonyl groups and the catalysis of Br2 were essential. Density functional theory (DFT) calculations indicated that carbonyl