Scheme 212. Intramolecular Borylation via Sequential B–Mes Bond Cleavage.
Reagents and conditions: (a)399t-BuLi and MesB(OMe)2, THF, −78 °C; (b) (1) BBr3, toluene, 110 °C, 24 h, (2) R–Li (2.4 equiv), THF or Et2O, −78 °C to rt, 12 h.
Reagents and conditions: (a)399t-BuLi and MesB(OMe)2, THF, −78 °C; (b) (1) BBr3, toluene, 110 °C, 24 h, (2) R–Li (2.4 equiv), THF or Et2O, −78 °C to rt, 12 h.