Table 3.

Aromatic C–H Borylation in m-Substituted Benzylamine Boranes

entry	substrate	X	R	para:ortho borylation	combined yield,a %
1	1	H	Me	37	94
2	41	Cl	Me	42:43, 25:1a (1:1.2)b	93c
3	44	I	Me	45:46, 40:1a (1:2.4)b	91c
4	47	Cl	(CH2)4	48:49, 10:1a	95
5	50	F	Me	51:52, 13:1a (4:1)b	95c
6	53	PhO	Me	54:55, 10:1a	96

^aCatalytic borylation conditions: 5 mol% Tf₂NH, PhMe, sealed tube, 160 °C, 14h, quenched with ca. 10 mol% n-Bu₄NBH₄.

^bStoichiometric borylation conditions: 0.9 equiv Ph₃C⁺ [B(C₆F₅)₄]⁻, PhBr, rt, 4h, quenched with ca. 1.1 equiv n-Bu₄NBH₄.

^c24 h.