Organoboron compounds Subject

The use of solid supported, recyclable catalysts, is a well-assessed technique in classic organic chemistry, and many exhaustive reviews dealing with this subject are available [105, 115]. The use of solid supported catalysts for library synthesis in solution has also been reported. Among others, Kobayashi et al. presented the use of a new supported scandium catalyst for 3CC reactions leading to solution libraries of amino ketones, esters, and nitriles (24-member model discrete library) [116], or to quinolines (15-member model discrete library) [117], and Jang [118] presented a polymer bound Pd-catalyzed Suzuki coupling of organoboron compounds with halides and triflates. This area was also briefly reviewed recently [119]. 

This chapter will concentrate primarily on features of the chemistry of diboron compounds of particular interest from the organometallic viewpoint. While our limited scope does not permit a comprehensive review of all aspects of diboron chemistry, we will initially survey some general features of the subject, with emphasis on unique synthetic aspects and on properties particularly characteristic of compounds containing a simple electron-pair bond between boron atoms. Electron-deficient polyboron compounds will be specifically excluded from consideration. More extensive consideration will be given to the interaction of diboron compounds with unsaturated organic systems, which is a major aspect of organometallic chemistry based on boron-boron-bonded systems. Finally, we shall survey some of the chemistry of particular organoboron compounds derived from diboron precursors. 

Two further methods of preparing organoboron compounds have been the subject of fairly recent detailed study, namely, reaction of boron halides with hydrocarbons and addition of boron hydrides to olefins. For instance, arylboron dihalides are formed when boron trihalides are heated with aromatic hydrocarbons, aluminum chloride, and aluminum powder,217 and phenyl-boron dibromide has been prepared analogously.218 Further, boron halides such as diboron tetrachloride and tetrafluoride add to olefins, yielding bis-(dichloroboryl) and bis(difluoroboryl) compounds 219... 

Palladium-catalyzed hydroboration, haloboration, and similar reactions involving addition of organoboron compounds to alkynes have been reviewed.Alkylborane addition to alkynes followed by intra- or intermolecular cross-coupling with a vinyl halide or triflates according to the Suzuki-Miyaura protocol constitutes a very powerful synthetic route for the generation of two carbon-carbon bonds in cascade. This subject and its applications in synthesis have been reviewed. ... 

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