The Preparation Of Aryl Boronic Acid With Organic Zinc Reagent And The Study Of It’s Coupling Reactions

Aryl boronic acid is relatively stable in the air, less sensitive to moisture, long-term preservation and high reactivity, so that a variety of substituted aromatic ring boric acid as an important intermediate in organic synthesis as well as pharmaceuticals, chemicals, pesticide intermediates[1-2], it is an important raw material for Suzuki cross-coupling reaction[3], may form C-O bond, C-N bond, C-S bond, can also happen conjugate reaction with α,β-unsaturated carboxyl compound[4], and synthesis dyes, liquid crystal display material intermediates, biosensors and herbicides, is widely used in organic chemistry. Because of its low toxicity and degradation to the ultimate environmentally friendly boric acid, so a substituted aryl boronic acid compound is considered to be green.Since the organic zinc reagent with good functional group compatibility, high chemical regional and stereo selectivity,etc. the subject with organic zinc reagent as a nucleophilic reagent, trimethyl borate as the electrophile reagent, at the conditions of room temperature and anaerobic have synthesised various functional groups of the aryl boronic acid and was characterized. The influence of the main factors of reaction temperature, reaction time, material ratio to synthetic reaction yield was studied, and its most important applications Suzuki coupling reaction was investigated.This thesis is divided into three parts:Part I: summary of the application of substituted aryl boronic acid, three synthesis methods of aryl boronic:organic lithium reagent; Grignard reagent; palladium catalytic oxidation of boron-based method, and the application and preparation method of organic zinc reagent.Part II: Preparation of aryl boronic acid with organic zinc reagent.In this paper, the synthetic step and route of organic zinc reagent preparing aryl boronic acid has been described, and the reaction conditions were optimized and expanded substrate to give a series of aryl boronic acid, and by 1HNMR, 13 CNMR the products have been characterized, The method mentioned above has features of easy-operated and higher yield. It is worth mentioning that the disulfides are also potential synthetic intermediates.Part III: Suzuki coupling reactionBy the use of aryl borate with halogenated hydrocarbons directly "one-pot" Suzuki coupling reaction,the use of aryl boronic acid benzyl ester avoid the occurrence of partial boron removal effect and partly dehydrated to form acid anhydride, to reduce loss during the reaction of boric acid. The "one-pot" aryl boronic ester without purification was used directly in the Suzuki reaction, The feasibility of this method has been verified with both high yield and fast reaction rate, which can be considered as a new approach for the Suzuki reactions.