Synthesis Of A Novel Boron Reagent And Its Application In The Chiral Recognition Of Chiral Diols

Chirality is a fundamental property of nature.Chiral compounds are widely used in life science,chemistry,pharmacy,and many other fields,and the demand is increasing year by year.Therefore,it is particularly important to study chiral testing methods and develop efficient chiral recognition methods for the preparation and high-throughput testing of chiral compounds.The nuclear magnetic test method based on chiral reagents has the advantages of convenient operation,fast speed,low cost,no need for standard substances,and no need to make a standard curve,so it has been one of the most widely used methods for studying chiral recognition.Chiral diols have been widely used in related fields such as pesticides,medicine,and chemical industry due to their unique properties,and their chiral structure plays a key role in their own properties.The identification method is of great significance.This work reports the design and synthesis of a novel chiral boron reagent and its application in the recognition of chiral diols.The details are as follows:The new boron reagent was synthesized in this way,using chiral 1,2-diphenyl ethylenediamine as the chiral source,first monoprotected by the phthaloyl group,a nd then reductively aminated with o-formylphenylboronic acid and intramolecular n ucleophilic substitution and reduction（a three-step tandem reaction）.The reagent h as a novel bridging skeleton,and its structure was confirmed by X-ray test single crystal,and its spectral signal had been clearly assigned by ¹HNMR,¹³C NMR,H MBC and COSY.As a chiral derivating agent for NMR,the new boron reagent was used for chiral recognition of chiral diols.It was found that the H_A signal on the boron reagent of the derivative has a large chemical shift difference,which can be used as a characteristic signal peak for chiral diol identification.By optimizing the derivatization conditions,the best test conditions were determined,the accuracy of the method for the determination of the ee values of diols by the reagent was verified,and 12 kinds of chiral diol substrates of various structural types were expanded,all of which achieved very good results（chemical shift differences are 0.06-0.39 ppm）.This boron reagent has the advantages of simple synthesis,fast derivatization reaction,clear spectra without overlap,obvious chemical shift differences of derivatized products,easy analysis,accurate test results,wide application of substrates so on.It can be used as a general NMR method to identify chiral diols.In addition,reasonable discussions and explanations on the recognition mechanism and the scope of substrate application were given,which provided new research ideas for the research in this field.