Bismuth(III) acetate is a safe, inexpensive, and selective facilitator of sequential protodeboronations, which when used in conjunction with Ir-catalyzed borylations allows access to a diversity of borylated indoles. The versatility of combining Ir-catalyzed borylations with Bi(III)-catalyzed protodeboronation is demonstrated by selectively converting 6-fluoroindole into products with Bpin groups at the 4-, 5-, 7-, 2,7-, 4,7-, 3,5-, and 2,4,7-positions and the late-stage functionalization of sumatriptan.
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http://dx.doi.org/10.1021/acs.orglett.6b00356 | DOI Listing |
J Org Chem
December 2024
State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130021, China.
Silyl-phenanthroline (NN'Si) ligand ancillary iridium-catalyzed C(sp)-H borylation is investigated theoretically. Density functional theory calculations clearly disclose that the (NN'Si)Ir(H)(Bpin) (NN'Si = 6-[(di--butylsilyl)methyl]-1,10-phenanthroline) complex is a resting state, and the (NN'Si)Ir(Bpin) complex serves as an active species in the catalytic cycle. The remarkably high activity of this type of a catalyst arises from the rapid reductive elimination of HBpin from (NN'Si)Ir(H)(Bpin) to generate the active species (NN'Si)Ir(Bpin).
View Article and Find Full Text PDFInorg Chem
September 2024
Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, China.
Iridium-catalyzed C-H borylation of aromatic and aliphatic hydrocarbons assisted by a directing group was theoretically investigated. Density functional theory (DFT) calculations revealed both Ir-catalyzed C(sp)-H and C(sp)-H borylations via an Ir/Ir catalytic cycle, where the tetra-coordinated (C, N)Ir(Bpin) complex with two vacant sites is an active species. Dramatically, the orientation of cyclometalation for C(sp)-H bond activation assisted by a directing group is different from the C(sp)-H one.
View Article and Find Full Text PDFChimia (Aarau)
August 2024
Research Chemistry, Syngenta Crop Protection AG, Schaffhauserstrasse 101, Stein AG CH-4332, Switzerland.
Direct borylation of C-H bonds is a privileged strategy to access versatile building blocks and valuable derivatives of complex molecules (late-stage functionalization, metabolite synthesis). This perspective aims to provide an overview and classification of the catalytic systems developed in this fast-growing area of research. Unexpected selectivity differences between two established directed-borylation systems have been discovered using high-throughput experimentation highlighting the importance of classical control experiments in catalysis research.
View Article and Find Full Text PDFJ Am Chem Soc
September 2024
State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
The indole moiety is ubiquitous in natural products and pharmaceuticals. C-H borylation of the benzenoid moiety of indoles is a challenging task, especially at the C5 position. We have combined computational and experimental studies to introduce multiple noncovalent interactions, especially dispersion, between the substrate and catalytic ligand to realize C5-borylation of indoles with high reactivity and selectivity.
View Article and Find Full Text PDFOrg Lett
August 2024
Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X7, Canada.
The total synthesis of tanshinone IIA and related bioactive diterpenes isolated from the Chinese plant was completed from a common tetralin building block. The synthetic route highlights a 3,4-disubstituted furan synthesis and various regioselective C-H functionalization reactions, including a Pd catalyzed iodination and an Ir catalyzed borylation, along with an intramolecular stanna-Brook type reaction to construct the -quninone ring of the target molecule.
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