TY - JOUR
T1 - Against All Odds, Uranium and Thorium Iminato Complexes Enable the Cleavage of C═O Bonds in Isocyanates
AU - Makarov, Konstantin
AU - Ritacco, Ida
AU - Fridman, Natalia
AU - Caporaso, Lucia
AU - Eisen, Moris S.
N1 - Publisher Copyright:
© 2023 American Chemical Society.
PY - 2023/9/1
Y1 - 2023/9/1
N2 - The catalytic activity of actinide-based catalysts is presented herein for the hydroboration and deoxygenation of isocyanates with pinacolborane (HBpin). A modified class of ligand systems possessing a five-membered ring core constructing the N-heterocyclic iminato moiety is introduced. All actinide complexes showed very good catalytic activities under mild conditions, with low catalyst loadings achieving almost quantitative yields. A wide number of isocyanates were studied including aliphatic isocyanates, aromatic isocyanates, and diisocyanates yielding to the corresponding borylated N-methyl amines and the borylated formamides, which are easily hydrolyzed toward the free amines and formamides. These organoactinide catalysts exhibited a great functional group tolerance toward methoxy, amido, and halides. The reaction selectivity was thoroughly investigated and exhibited a very good selectivity toward the isocyanate functionality having double or triple unsaturated C-C bonds. Kinetic studies were performed in order to establish the rate order dependency on the concentrations of the organoactinide complex, HBpin, and isocyanate. A proposed mechanism is presented based on experiments affording a more comprehensive understanding of the experimental activity trends and reinforced by the stoichiometric reaction studies, thermodynamic measurements, deuterium-labeling experiments, and theoretical DFT calculations.
AB - The catalytic activity of actinide-based catalysts is presented herein for the hydroboration and deoxygenation of isocyanates with pinacolborane (HBpin). A modified class of ligand systems possessing a five-membered ring core constructing the N-heterocyclic iminato moiety is introduced. All actinide complexes showed very good catalytic activities under mild conditions, with low catalyst loadings achieving almost quantitative yields. A wide number of isocyanates were studied including aliphatic isocyanates, aromatic isocyanates, and diisocyanates yielding to the corresponding borylated N-methyl amines and the borylated formamides, which are easily hydrolyzed toward the free amines and formamides. These organoactinide catalysts exhibited a great functional group tolerance toward methoxy, amido, and halides. The reaction selectivity was thoroughly investigated and exhibited a very good selectivity toward the isocyanate functionality having double or triple unsaturated C-C bonds. Kinetic studies were performed in order to establish the rate order dependency on the concentrations of the organoactinide complex, HBpin, and isocyanate. A proposed mechanism is presented based on experiments affording a more comprehensive understanding of the experimental activity trends and reinforced by the stoichiometric reaction studies, thermodynamic measurements, deuterium-labeling experiments, and theoretical DFT calculations.
KW - C═O bond cleavage
KW - N-heterocyclic imine
KW - actinides
KW - homogeneous catalysis
KW - isocyanate hydroboration
UR - http://www.scopus.com/inward/record.url?scp=85170029409&partnerID=8YFLogxK
U2 - 10.1021/acscatal.3c02241
DO - 10.1021/acscatal.3c02241
M3 - 文章
AN - SCOPUS:85170029409
SN - 2155-5435
VL - 13
SP - 11798
EP - 11814
JO - ACS Catalysis
JF - ACS Catalysis
IS - 17
ER -