| Organoboron compounds are not only an important component of polymer chemistry,materials,chemical sensors,and bioactive molecules,they are also popular as effective synthetic building blocks.Therefore,it is always appealing to discover and develop highly efficient methods for the constructions and transformations of organoboron compounds in synthetic chemistry,material sciences as well as pharmaceutics.Our research group has been focused on the synthesis,transformations as well as applications of organoboron compounds in recent years.This dissertation will mainly focus on the study of green and practical methods for the preparation of organoboron compounds as well as their valuable elaborations:Domino-Borylation-Protodeboronation(DBP)strategy in alkynes and utilization of readily available organoborons as a nucleophile to achieve 1,2-difunctionalization of olefins.There are six aspects in this dissertation:1)The application of base-promoted DBP strategy in common alkynes:A catalytic amount of potassium carbonate catalyzed the cis-1,2-diboronation of various alkynes with B2pin2(pinacol diborates)was innovatively developed to efficiently synthesize cis-1,2-bis(boryl)alkenes.This method has the advantages of high yield,high selectivity,and no transition metal involvement.With Suzuki–Miyaura reaction,cis-1,2-bis(boryl)alkenes can be efficiently converted into tetrasubstituted multi-aryl olefins and phenanthrene derivatives.2)The application of base-promoted DBP strategy in propynols:A catalytic amount of potassium carbonate catalyzed borylation of propynols with B2pin2was developed to efficiently provide tetrasubstituted alkenylboronates.This strategy is compatible with a broad range of functional groups.Tetrasubstituted alkenylboronates can be readily derivatized into?-diketones as well as tetrasubstituted olefins.3)The application of base-promoted DBP strategy in 1,2-diarylacetylene:A catalytic amount of potassium carbonate catalyzed the reductive diborylation of 1,2-diarylacetylene was innovatively developed to efficiently synthesize anti-vicinal diboronates.This strategy has good functional group compatibility and excellent stereoselectivity.With cesium carbonate and deuterated methanol,the products can be easily deuterated in situ,and selectively rendered1,2-dideuterium compounds and 1,1,2,2-tetradeuterium compounds.4)Palladium-catalyzed 1,2-hydroarylation of?,?-unsaturated amide compounds was achieved with alkyl?-borate generated in situ.With the help of hydroboration and C(sp~3)-C(sp~2)coupling,copper/palladium co-catalyzed intramolecular 1,2-hydroarylation of?-,?-unsaturated amide can be achieved,resulting in the facile construction of 3,4-dihydroquinolones.The products can be gently oxidized by dimethyl sulfoxide to quinolones,which are the main ingredient of pesticides.5)Palladium-catalyzed 1,2-diarylation of vinylarenes at ambient temperature was achieved with the commercially available arylboronic acids.Palladium-catalyzed three-component coupling of olefins is mildly and efficiently achieved with arylboronic acids and aryldiazonium salts as coupling reagents to regioselectively synthesize 1,2-diarylated products.This strategy can simultaneously introduce two different aryl groups,providing multi-aryl-substituted ethane derivatives.1,1-Disubstituted olefins are well compatible for the first time,resulting in the formation of two new carbon-carbon bonds and a new quaternary carbon center.6)Palladium-catalyzed regioselective 1,2-arylalkenylation of vinylarenes at ambient temperature was achieved with the commercial accessible arylboronic acids.Palladium-catalyzed three-component coupling of olefins is efficiently achieved with arylboronic acids and vinyl triflates as coupling reagents to regioselectively synthesize 1,2-arylalkenylated products at ambient temperature.This strategy is not only compatible with 1,1-disubstituted olefins to form quaternary carbon centers,but also extends the substrate scope to simple aryl olefins. |
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