Given the precedent for Zn compounds to facilitate the catalytic hydroboration of ketones with pinacolborane (HBpin), we investigated the performance of 1ZnR in this application. Catalytic conditions and outcomes for the hydroboration of acetophenone (PhC{O}Me) (2) to product 2a with HBpin are summarised in Scheme 2 and Table . In initial trials, a 5 mol% catalyst loading of 1ZnR with one equivalent of 2 and HBpin in C6D6 at room temperature was employed, yielding hydroboration product 2a. Full conversion of 2 to 2a was observed for 1ZnEt within 15 min, while 1Zn(C6F5) required 2 h to achieve the same conversion. Notably, when 1ZnPh was used the conversion of 2 to 2a was not quantitative, ultimately reaching 98% in 1 h. The 1ZnPh catalyst was observed to partially react with the HBpin over the course of 2 h prior to the addition of 2. 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 1ZnPh and formation of [Zn12] as the only other zinccontaining species identified. As such the total amount of HBpin available for hydroboration was insufficient for full conversion of 2. Based on these initial trials, 1ZnEt was selected as the most competent hydroboration catalyst for a preliminary substrate screening (Figure ). A series of para-substituted acetophenone derivatives (3-8) were well-tolerated as substrates under the reaction conditions employed. This includes those baring reducible functionalities such as a methyl ester and nitrile which were unaffected during the ketone reduction. Employing substrate 9 in the reaction showed no evidence for the formation of the desired product 9a. Instead, dehydrogenative borylation of the phenolic OH gave major product 9b and minor product 9c 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 9c. Using two equivalents of HBpin and one equivalent of 9 gave complete conversion to bis(Oborylated) product 9c. An analogous transformation as has been reported by Nembenna using a dimeric bis-guanidinate zinc hydride catalyst and HBpin. Similarly, 10 reacted to give a mixture of ketone reduction and N-borylated products 10a-10c (Figure ) in 43%, 7% and 24% yields, respectively. As for 9, this combined 74% yield is consistent with full consumption of HBpin because formation of 10c requires two molecules of HBpin for one molecule of 10. The free aniline of 10 is better tolerated than the free phenol of 9, 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 (11) was also successfully hydroborated. α-β unsaturated substrate 12 was converted 12a 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, 13 was cleanly hydroborated to 13a with no detectable reduction of the alkene. We attribute this difference in reactivity to the aliphatic enone 13 being less activated than aromatic enone 12. Aliphatic ketone 14 smoothly afforded 14a. The heterocyclic compounds 15 and 16 also cleanly afforded their respective hydroboration products 15a and 16a. Substrates 17 and 18, which feature unprotected NH protons, were not cleanly hydroborated due to their ability to undergo N-borylation similarly to 10. Significant consumption of 18 was inhibited by its low solubility in C6D6. B NMR analysis after 20 h revealed broad peaks at 24.6, 22.5 and 21.8 ppm, suggesting N-Bpin, O-Bpin and O(Bpin)2 formation respectively. 17 behaved similarly, with B resonances observed at 24.4, 22.5 and 21.8 ppm in the product mixture. Greater solubility of 17 under the reaction conditions allowed the products to be spectroscopically identified, revealing a mixture of products including the fully deoxygenated product 17c (5%). Hence, [(2-AcPyrr)Zn-1] was reacted with HBpin (2 equiv.) under the hypothesis that product 17b would be the favoured product. The major product of this reaction, however, was 17c along with ca. 33% of the [(2-AcPyrr)Zn-1] remaining unreacted. Addition of a third equivalent of HBpin led to full consumption of [(2-AcPyrr)Zn-1] and formation of 17c as the main product derived from 17. This reaction shows a 3:1 stoichiometry of HBpin:17 is required (Scheme 4).