Other ligands and their Ir complexes used for the catalytic dehydrogenative
borylation of arenes are summarized in Fig. 5. Complexes 113–115 exhibited typical
regioselectivities in the borylation of mono- and di-substituted arenes [216–
218]. Maleczka and Smith et al. reported that Ir-dpm and -dmadpm complexes
exhibited high regioselectivities for the borylation of 1,3- or 1,4-disubstituted arenes
with small substituents such as fluorine [219].
Apart from arene borylation, the dehydrogenative borylation of alkyl groups
remains rare. Yamaguchi and Itami et al. reported the dehydrogenative borylation
of cyclopropanes using a catalytic system of [Ir(OMe)(cod)] 2 with tmphen ligand
[207], which had been proven to be effective for the borylation of the same substrate
Scheme 86 Directed dehydrogenative borylation. (a) Bpza group-directed borylation. (b)
Phosphinomethyl group-directed borylation. (c) Pyridylmethyl group-directed borylation
Fig. 5 Ligands and complexes for Ir-catalyzed dehydrogenative borylation of arenes
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T. Shimbayashi and K. Fujita