Laser-ablated boron atoms react with methanol to give primarily CH3BO, which is isolated in an argon matric. FTIR spectra of various isotopic combinations and MP2 calculated isotopic frequencies help identify this product and the minor products, CH2BOH and CH2BO. All new products form via boron insertion into the C-O bond, while HBO and DBO form via boron insertion into the O-H bond; no C-H insertion products can be observed. All of these products contain partial dative B-O bonds in which an oxygen lone pair bonds with the empty boron p-orbital.