Regioselective electrophilic borylation of haloarenes

Abstract

Haloarenes undergo direct borylation using amine : BCl3 : AlCl3 in the ratio of 1 : 1 : 2. After esterification the pinacol boronate esters are isolated in good yield with regioselectivity controlled by steric and electronic effects.

An Investigation of the Symmetric and Asymmetric Cleavage Products in the System Aluminum Trihalide/1‐Butylimidazole

“…However,i nteractions of MeCN with the complexes in mixtures with x(AlBr 3 ) > 0.40 result in the formation of mixed complexes with both ligands (see Figures S8 and S9 of the Supporting Information). Figure 1s hows 15 Nc hemical shift of N3 in BuIm is more influenced by coordination than that of N1. Dichloromethane was used for the NMR spectroscopicc haracterization of all AlCl 3 /BuIm mixtures.…”

“…Between x(AlBr 3 ) = 0a nd 0.40 acetonitrile (MeCN) is ag ood solventd ue to the better donora bility of BuIm compared to MeCN. All mixturesw ere analyzed with ac ombination of 1D 1 Ha nd 27 Al as well as 2D 1 H, 13 Cand 1 H, 15 N NMR correlation experiments. However,i nteractions of MeCN with the complexes in mixtures with x(AlBr 3 ) > 0.40 result in the formation of mixed complexes with both ligands (see Figures S8 and S9 of the Supporting Information).…”

“…There is no sign of the presence of an octahedrally coordinated cation sucha s [Al(BuIm) 6 ] 3 + or [AlBr 2 (BuIm) 4 ] + .H owever,ac ation must be present in both mixtures, as the bandso f[ Al 2 Br 7 ] À are unambiguously detected in their Raman spectra. By 1 H, 15 [4,14,15] Additionally,t here are no reports on the characterization of the cations[ AlX(L) 3 ] 2 + and [Al(L) 4 ] 3 + by 27 Al NMR spectroscopy in LCCs. By 1 H, 15 [4,14,15] Additionally,t here are no reports on the characterization of the cations[ AlX(L) 3 ] 2 + and [Al(L) 4 ] 3 + by 27 Al NMR spectroscopy in LCCs.…”

“…The dominant bandsi nt he IR and Ramans pectraa sw ell as the 27 Al and the 15 [42] Conclusions Sixteen AlBr 3 -a nd five AlCl 3 -based mixturesw ith the ligand BuIm were synthesized and characterized by multinuclear and multidimensional NMR, mid-IR,f ar-IR, and Raman spectroscopy and in part by single-crystal X-ray diffraction.Wecould demonstrate that 2D 1 H, 13 Ca nd 1 H, 15 NN MR experiments supporting 4 ] + ! [AlBr 3 (BuIm)]/"[AlBr 2 (BuIm) 2 ] + ".…”

“…Dominant vibrational bands,27 Al chemicalshifts and their full widths at half-maximum Dn 1/2 ,a nd15 Nc hemical shifts of the identified complexes. [a] "[AlCl 2 (BuIm) 2 ] + "[AlCl 3 (BuIm)] [a] Italicf onti ndicates tentativea ssignments.…”