Alkylboron reagents

In addition, with respect to the Suzuki coupling, various alkylboron reagents have also been successfully coupled with electrophile partners. 

As in the Negishi reaction, various alkylboron reagents have also been successfully coupled with electrophile partners. Suzuki et al. coupled 1-bromo-l-phenylthioethene with 9-[2-(3-cyclohexenyl)ethyl]-9-BBN (27), prepared by a simple addition of 9-borabicyclo[3.3.1]nonane (9-BBN) to 4-vinyl-1-hexene (26), to furnish 4-(3-cyclohexenyl)-2-phenylthio-1-butene (28) in good yield [36],... 

These reactions are likely to occur by oxidative addition through a radical mechanism, as evidenced by the loss of stereochemistry of the starting alkyl halide during the coupling process (Equation 19.14b). Despite the radical mechanism, some reactions of benzylic electrophiles have been conducted enantioselectively (Equation 19.14c). Even reactions of alkylboron reagents witti secondary alkyl halides catalyzed by nickel complexes have now been reported. These reactions were conducted with nickel precursors in combination with trflns-l,2-cyclohexanediamine (Equation 19.14d). ... 

Following this first study, Yu et al. [60] reported the use of the less toxic alkylboron reagents, including methylboroxine and boronic acids, in the C-H alkylation of arenes as well as alkanes containing a pyridine or quinoline directing group (Scheme 19.39). 

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