Organoboron compounds are valuable reagents that provide immediate access to a variety of synthetic transformations for C-C and C-X bond formation. While their widespread use is historically framed within transition metal-catalyzed crosscoupling reactions (e.g., Suzuki-Miyaura, Chan-Lam ), modern organoboron chemistry provides broad and bespoke reactivity as reagents, catalysts, additives, materials and drug candidates. As such, the installation of boron functional groups continues to be a very active field of methodological development. Classical approaches to boron installation, such as the use of organometallics 1,612-14 and hydroboration, 1,6,15-18 have been supplemented by contemporary methodologies including photoredox catalysis and C-H activation. A particularly powerful approach to the formation of complex organoboron compounds has been enabled through single carbon homologations. Pioneered by this approach uses a carbenoid as the key reagent to induce a stereospecific 1,2metallate rearrangement (Scheme 1a). This general strategy has seen significant development in elegant work by Aggarwal, leading to powerful platforms for iterative synthesis. The first catalytic asymmetric approach to the 1,2-metallate rearrangement of lithium boronates was recently reported by Jacobsen. All existing metalate rearrangements require the use of stoichiometric organolithium, -magnesium, or -zinc reagents. Here we show an alternative conceptual approach to organoboron homologation using chemoselective Pd-catalyzed cross-coupling. This method does not require stoichiometric organometallics and instead relies upon a relatively rare oxidative addition to halomethylorganoboron reagents combined with chemoselective transmetalation (Scheme 1b). Halomethylorganoboron reagents have been shown to display several different reactivity profiles, including metalation, boronate formation, and the formation of a-boryl radicals; however, examples of oxidative addition to this reagent class remain rare and are principally achieved using Ni catalysis. For example, Fu demonstrated stereoconvergent crosscoupling of racemic a-chloroboronic acid esters with organozinc reagents, while Martin first showed crosselectrophile coupling and alkene difunctionalization using a-bromoboronic acid esters. Within Pd catalysis, Gevorgyan has developed Heck reactions based on a single-electron transfer (SET) manifold. To our knowledge, the only example of a direct oxidative addition of Pd(0) to a halomethylboronic acid ester was shown by Falck in the context of Stille reactions. We hypothesized that a formal C1 homologation of a boronic acids could be achieved using a halomethylorganoboron reagent as the surrogate carbenoid. Selective engagement of this reagent as the electrophilic component in a chemoselective Suzuki-Miyaura cross-coupling with a boronic acid would deliver a benzylic BPin product without the use of organometallic reagents. This approach would be contingent upon several key control elements: (i) chemoselective transmetalation of the arylboronic acid over the halomethyl BPin, (ii) inhibition of organoboron group transesterification (speciation), (iii) inhibition of product transmetalation, which would lead to oligo-or polymerization, and (iv) inhibition of BPin hydrolysis (of starting material and product). Control of BPin hydrolysis was particularly important as the corresponding boronic acids are unstable and prone to rapid protodeboronation. Indeed, very few benzylic boronic acids and esters are commercially available, especially in comparison to the equivalent aryl reagents. Enabling the formal homologation of arylboronic acids to benzyl BPin would provide straightforward access to this underrepresented molecular space.