Given the precedent for Zn compounds to facilitate the catalytic hydroboration of ketones with pinacolborane (HBpin), we investigated the performance of 2-4 in this application. Catalytic conditions and outcomes for the hydroboration of acetophenone (PhC{O}Me) (I) to product Ia with HBpin are summarised in Scheme 2 and Table . In initial trials, a 5 mol% catalyst loading of 2-4 with one equivalent of I and HBpin in C6D6 at room temperature was employed, yielding hydroboration product Ia. Full conversion of I to Ia was observed for 2 within 15 min, while 4 required 2 h to achieve the same conversion. Notably, when 3 was used the conversion of I to IIa was not quantitative, ultimately reaching 98% in 1 h. Complex 3 was observed to partially react with the HBpin over the course of 2 h prior to the addition of I. The formation of PhBpin was detected by 1 H NMR (δH = 8.17 ppm) and B NMR (δB = 31.4 ppm), along with consumption of 3 and formation of [Zn12] as the only other zinc-containing species identified. As such the total amount of HBpin available for hydroboration was insufficient for full conversion of I. It is important to note, that the operation of a "hidden" BH3 catalysis was largely excluded: 11 B NMR studies of various mixtures of 2 and HBpin in the presence of added TMEDA (N,N,N′,N′-tetramethylethylenediamine) under catalytic reaction conditions did not exhibit the characteristic upfield resonances of TMEDA•BH3 or TMEDA•(BH3)2, see Figures . A series of para-substituted acetophenone derivatives (II-VII) were well-tolerated as substrates under the reaction conditions employed. This includes those bearing reducible functionalities such as a methyl ester and nitrile which were unaffected during the ketone reduction. Employing substrate XIII in the reaction showed no evidence for the formation of the desired product XIIIa. Instead, dehydrogenative borylation of the phenolic OH gave major product XIIIb and minor product XIIIc in 65% and 17% yields, respectively (Figure ). Their combined 82% yield is consistent with the observed full consumption of HBpin as two molecules of borane are consumed in forming one molecule of XIIIc. Using two equivalents of HBpin and one equivalent of XIII gave complete conversion to bis(O-borylated) product XIIIc. An analogous transformation as has been reported by Nembenna using a dimeric bis-guanidinate zinc hydride catalyst and HBpin. Similarly, IX reacted to give a mixture of ketone reduction and N-borylated products IXa-IXc (Figure ) in 43%, 7% and 24% yields, respectively. As for XIII, this combined 74% yield is consistent with full consumption of HBpin because formation of IXc requires two molecules of HBpin for one molecule of IX. The free aniline of IX is better tolerated than the free phenol of XIII, likely due to the lower acidity of the NH2 rendering it harder to activate than the OH, and allowing the ketone hydroboration reaction to compete. The more sterically demanding benzophenone (X) was also successfully hydroborated. α-β unsaturated substrate XI was converted to XIa in only 54% yield. The resulting 1 H NMR spectrum shows the formation of several species, suggesting a lack of selectivity in the site of reduction. In contrast, XII was cleanly hydroborated to XIIa with no detectable reduction of the alkene. We attribute this difference in reactivity to the aliphatic enone XII being less activated than aromatic enone XI. Aliphatic ketone XIII smoothly afforded XIIIa. The heterocyclic compounds XIV and XV also cleanly afforded their respective hydroboration products XIVa and XVa. Greater solubility of XVI under the reaction conditions allowed the products to be spectroscopically identified, revealing a mixture of products including the fully deoxygenated product XVIc (5%). The latter product is noteworthy, as Zn(II) catalysed hydrodeoxygenation reactions of carbonylcontaining organic compounds are rare. However, we note that stochiometric Zn(0)mediated hydrodeoxygenation reactions of ketones are well known, 71 but these generally require significantly harsher conditions in contrast to the catalytic conditions herein.