{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"submitter":["Grundy ME"],"funding":["European Research Council"],"pagination":["2286-2294"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC9942201"],"repository":["biostudies-literature"],"omics_type":["Unknown"],"volume":["13(4)"],"pubmed_abstract":["[(NacNac)Zn(DMT)][B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>], <b>1</b>, (NacNac = {(2,6- <sup><i>i</i></sup> Pr<sub>2</sub>H<sub>3</sub>C<sub>6</sub>)N(CH<sub>3</sub>)C}<sub>2</sub>CH), DMT = <i>N,N</i>-dimethyl-4-toluidine), was synthesized via two routes starting from either (NacNac)ZnEt or (NacNac)ZnH. Complex <b>1</b> is an effective (pre)catalyst for the C-H borylation of (hetero)arenes using catecholborane (CatBH) with H<sub>2</sub> the only byproduct. The scope included weakly activated substrates such as 2-bromothiophene and benzothiophene. Computational studies elucidated a plausible reaction mechanism that has an overall free energy span of 22.4 kcal/mol (for <i>N</i>-methylindole borylation), consistent with experimental observations. The calculated mechanism starting from <b>1</b> proceeds via the displacement of DMT by CatBH to form [(NacNac)Zn(CatBH)]<sup>+</sup>, <b>D</b>, in which CatBH binds via an oxygen to zinc which makes the boron center much more electrophilic based on the energy of the CatB-based LUMO. Combinations of <b>D</b> and DMT act as a frustrated Lewis pair (FLP) to effect C-H borylation in a stepwise process via an arenium cation that is deprotonated by DMT. Subsequent B-H/[H-DMT]<sup>+</sup> dehydrocoupling and displacement from the coordination sphere of zinc of CatBAr by CatBH closes the cycle. The calculations also revealed a possible catalyst decomposition pathway involving hydride transfer from boron to zinc to form (NacNac)ZnH which reacts with CatBH to ultimately form Zn(0). In addition, the key rate-limiting transition states all involve the base, thus fine-tuning of the steric and electronic parameters of the base enabled a further minor enhancement in the C-H borylation activity of the system. Outlining the mechanism for all steps of this FLP-mediated process will facilitate the development of other main group FLP catalysts for C-H borylation and other transformations."],"journal":["ACS catalysis"],"pubmed_title":["Understanding and Expanding Zinc Cation/Amine Frustrated Lewis Pair Catalyzed C-H Borylation."],"pmcid":["PMC9942201"],"funding_grant_id":["769599"],"pubmed_authors":["Grundy ME","Ingleson MJ","Yuan K","Bisai MK","Macgregor SA","Sotorrios L"],"additional_accession":[]},"is_claimable":false,"name":"Understanding and Expanding Zinc Cation/Amine Frustrated Lewis Pair Catalyzed C-H Borylation.","description":"[(NacNac)Zn(DMT)][B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>], <b>1</b>, (NacNac = {(2,6- <sup><i>i</i></sup> Pr<sub>2</sub>H<sub>3</sub>C<sub>6</sub>)N(CH<sub>3</sub>)C}<sub>2</sub>CH), DMT = <i>N,N</i>-dimethyl-4-toluidine), was synthesized via two routes starting from either (NacNac)ZnEt or (NacNac)ZnH. Complex <b>1</b> is an effective (pre)catalyst for the C-H borylation of (hetero)arenes using catecholborane (CatBH) with H<sub>2</sub> the only byproduct. The scope included weakly activated substrates such as 2-bromothiophene and benzothiophene. Computational studies elucidated a plausible reaction mechanism that has an overall free energy span of 22.4 kcal/mol (for <i>N</i>-methylindole borylation), consistent with experimental observations. The calculated mechanism starting from <b>1</b> proceeds via the displacement of DMT by CatBH to form [(NacNac)Zn(CatBH)]<sup>+</sup>, <b>D</b>, in which CatBH binds via an oxygen to zinc which makes the boron center much more electrophilic based on the energy of the CatB-based LUMO. Combinations of <b>D</b> and DMT act as a frustrated Lewis pair (FLP) to effect C-H borylation in a stepwise process via an arenium cation that is deprotonated by DMT. Subsequent B-H/[H-DMT]<sup>+</sup> dehydrocoupling and displacement from the coordination sphere of zinc of CatBAr by CatBH closes the cycle. The calculations also revealed a possible catalyst decomposition pathway involving hydride transfer from boron to zinc to form (NacNac)ZnH which reacts with CatBH to ultimately form Zn(0). In addition, the key rate-limiting transition states all involve the base, thus fine-tuning of the steric and electronic parameters of the base enabled a further minor enhancement in the C-H borylation activity of the system. Outlining the mechanism for all steps of this FLP-mediated process will facilitate the development of other main group FLP catalysts for C-H borylation and other transformations.","dates":{"release":"2023-01-01T00:00:00Z","publication":"2023 Feb","modification":"2025-04-06T19:40:45.75Z","creation":"2025-02-18T22:53:38.04Z"},"accession":"S-EPMC9942201","cross_references":{"pubmed":["36846822"],"doi":["10.1021/acscatal.2c05995"]}}