Abstract
Chemodivergent synthetic methodologies enable the efficient introduction of structural diversity into high-value organic products via simple chemical alterations. In this regard, C-H activation and functionalization of pyridinoid azines are important transformations in the synthesis of many natural products, pharmaceuticals, and functional materials. Reflecting on azinyl nitrogen lone-pair steric repulsion, its tendency to irreversibly coordinate metal ion catalysts, and the electron deficiency of pyridine, C-H functionalization at the important α-position remains challenging. Thus, developing earth-abundant catalysts for α-selective azine mono-functionalization is an attractive target for chemical synthesis. Here, the selective organolanthanide-catalyzed α-mono-borylation of a diverse series of 18 pyridines is reported using Cp*2LuCH(TMS)2(Cp∗ = η5-C5Me5) (TMS = SiMe3) and affording valuable precursors for subsequent functionalization. Experimental and theoretical mechanistic data reported here support the intermediacy of a C-H-activated η2-lanthanide-azine complex, followed by intermolecular α-mono-borylation via σ-bond metathesis. Notably, varying the lanthanide identity and substrate substituent electronic character promotes marked chemodivergence of the catalytic selectivity: smaller/more electrophilic lanthanide3+ions and electron-rich substrates favor selective α-C-H functionalization, whereas larger/less electrophilic lanthanide3+ions and electron-poor substrates favor selective B-N bond-forming 1,2-dearomatization. Such lanthanide series catalytic chemodivergence is, to our knowledge, unprecedented.
Original language | English (US) |
---|---|
Pages (from-to) | 17086-17096 |
Number of pages | 11 |
Journal | Journal of the American Chemical Society |
Volume | 144 |
Issue number | 37 |
DOIs | |
State | Published - Sep 21 2022 |
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry
Fingerprint
Dive into the research topics of 'Chemodivergent Organolanthanide-Catalyzed C-H α-Mono-Borylation of Pyridines'. Together they form a unique fingerprint.Datasets
-
CCDC 2115732: Experimental Crystal Structure Determination
Rothbaum, J. O. (Contributor), Motta, A. (Contributor), Kratish, Y. (Contributor), Marks, T. J. (Contributor) & Marks, T. J. (Contributor), Cambridge Crystallographic Data Centre, 2022
DOI: 10.5517/ccdc.csd.cc290lfc, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc290lfc&sid=DataCite
Dataset
-
CCDC 2115729: Experimental Crystal Structure Determination
Rothbaum, J. O. (Contributor), Motta, A. (Contributor), Kratish, Y. (Contributor), Marks, T. J. (Contributor) & Marks, T. J. (Contributor), Cambridge Crystallographic Data Centre, 2022
DOI: 10.5517/ccdc.csd.cc290lb8, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc290lb8&sid=DataCite
Dataset
-
CCDC 2115722: Experimental Crystal Structure Determination
Rothbaum, J. O. (Contributor), Motta, A. (Contributor), Kratish, Y. (Contributor), Marks, T. J. (Contributor) & Marks, T. J. (Contributor), Cambridge Crystallographic Data Centre, 2022
DOI: 10.5517/ccdc.csd.cc290l31, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc290l31&sid=DataCite
Dataset