Catalyst-free diboration and silaboration of alkenes and alkynes using bis(9-heterofluorenyl)s

Abstract

Diboration and silaboration reactions are prominent tools to introduce valuable functional groups into organic substrates. To date, most diboranes(4) and silylboranes used for this purpose are electronically and/or kinetically stabilized...

Neutral and Anionic Diboron Compounds Bearing Electron‐Precise B−B Bond

“…Until recently, the Wagner group reported a class of anionic diboron compounds (90-95) based on 9-borafluorenyl units (Figure 5). [72][73][74][75][76][77] In general, the preparation of this type of anionic diboron species can be realized through the reaction of neutral/mono-anionic diboron precursor with base (such as organolithium compounds). Interestingly, for the synthesis of compound 90, the formation of the BÀ B bond was realized through an usual approach by deprotonation of diborane( 6) derivatives (Scheme 28).…”

Hydrosilylation of BB triple bonds: catalyst- and reductant-free construction of B–Si bonds and B2Si heterocycles

“…The construction of B–Si bonds is often non-trivial, due to a general lack of nucleophilic reagents based on either boron or silicon. This is most frequently accomplished by: (a) nucleophilic attack of an alkali metal silyl species at a haloborane, 1 e ,2 (b) nucleophilic attack of an anionic boron species at a halo- or alkoxysilane, 3 (c) reactions of a silylene [R 2 Si:] with a tricoordinate boron species via either adduct formation or B–X bond insertion, 4 and hydroboration of disilenes. 5 In contrast, B–Si bond construction without an alkali-metal nucleophile or a silylene is limited to just a handful of isolated examples, for instance a silyl ligand migration to boron on a tantalum scaffold and an iridium-catalyzed hydrosilylation of a diborene.…”