TY - JOUR
T1 - Atom-efficient regioselective 1,2-dearomatization of functionalized pyridines by an earth-abundant organolanthanide catalyst
AU - Dudnik, Alexander S.
AU - Weidner, Victoria L.
AU - Motta, Alessandro
AU - Delferro, Massimiliano
AU - Marks, Tobin J.
N1 - Funding Information:
The authors acknowledge financial support from the National Science Foundation (NSF, grant no. CHE-1213235). A.S.D. is supported by the Camille and Henry Dreyfus Postdoctoral Program in Environmental Chemistry. V.L.W. thanks the NSF for a Graduate Research Fellowship. NMR instrumentation purchases at IMSERC at Northwestern University were supported by the NSF (CHE-1048773). Computational resources supporting this work were provided by the Northwestern University Quest High Performance Computing cluster (M.D.) and CINECA Award HP10CPZK0T 2013 (A.M.). The authors thank S. Kozuch (University of North Texas) for providing the AUTOF program and valuable suggestions and R.J. Thomson (Northwestern University) for helpful discussions.
PY - 2014/12
Y1 - 2014/12
N2 - Developing earth-abundant, non-platinum metal catalysts for high-value chemical transformations is a critical challenge to contemporary chemical synthesis. Dearomatization of pyridine derivatives is an important transformation to access a wide range of valuable nitrogenous natural products, pharmaceuticals and materials. Here, we report an efficient 1,2-regioselective organolanthanide-catalysed pyridine dearomatization process using pinacolborane, which is compatible with a broad range of pyridines and functional groups and employs equimolar reagent stoichiometry. Regarding the mechanism, derivation of the rate law from NMR spectroscopic and kinetic measurements suggests first order in catalyst concentration, fractional order in pyridine concentration and inverse first order in pinacolborane concentration, with C=N insertion into the La-H bond as turnover-determining. An energetic span analysis affords a more detailed understanding of experimental activity trends and the unusual kinetic behaviour, and proposes the catalystresting state and potential deactivation pathways.
AB - Developing earth-abundant, non-platinum metal catalysts for high-value chemical transformations is a critical challenge to contemporary chemical synthesis. Dearomatization of pyridine derivatives is an important transformation to access a wide range of valuable nitrogenous natural products, pharmaceuticals and materials. Here, we report an efficient 1,2-regioselective organolanthanide-catalysed pyridine dearomatization process using pinacolborane, which is compatible with a broad range of pyridines and functional groups and employs equimolar reagent stoichiometry. Regarding the mechanism, derivation of the rate law from NMR spectroscopic and kinetic measurements suggests first order in catalyst concentration, fractional order in pyridine concentration and inverse first order in pinacolborane concentration, with C=N insertion into the La-H bond as turnover-determining. An energetic span analysis affords a more detailed understanding of experimental activity trends and the unusual kinetic behaviour, and proposes the catalystresting state and potential deactivation pathways.
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U2 - 10.1038/nchem.2087
DO - 10.1038/nchem.2087
M3 - Article
AN - SCOPUS:84911493151
VL - 6
SP - 1100
EP - 1107
JO - Nature Chemistry
JF - Nature Chemistry
SN - 1755-4330
IS - 12
ER -