Upon increasing the base amount to 2.0 equivalent, the resonance at 6.9 ppm almost disappeared, but the peak at 4.3 ppm was retained. Further comparison of calculated and observed 1 H NMR analysis on the reaction mixture of I′ and t BuOK (2.0 equivalents) confirm the definite formation of the carbanion intermediate V′. The negative charge of intermediate V′ is calculated to be delocalized over the benzene ring, as supported by the upfield shifting of related hydrogen signals. previous conditions , r. Chemical shifts shown in red were computed with the Gauge-independent atomic orbital (GIAO) method at B972/pcSseg-2 level of theory . c, Enhanced reactivity of secondary and tertiary benzylic organoboronates for the cross-coupling with 4-cyanopyridine. d, Development of "one-pot" carbosilylation of aromatic alkenes with PhMe2SiBpin 2a and 4-cyanopyridine 3a, see Table in SI for optimization details. e, Computational analysis on the enhancing effect of t BuOK (in black line: with 1.0 equiv; in blue line, 2.0 equiv.)