Novel approach to aminocarboranes by mild amidation of selected iodo-carboranes.
A mild protocol for the palladium-catalyzed Buchwald-Hartwig amidation of icosahedral carboranes is described. Employing 2-dicyclohexylphosphino-2'-(N,N-dimethylamino)biphenyl (1) as a ligand and K(3)PO(4) as a base, benzamide, trifluoroacetamide, acetamide, and formamide were coupled to a series of mono- and di-iodo carboranes furnishing the respective carborane derivatives in good to excellent yields. Subsequent base-mediated saponification of the trifluoroacetamide derivatives was shown to provide the free aminocarboranes. The structures of N-(1,7-dicarba-closo-dodecaboran-9-yl)benzamide (8a), N-(1,7-dicarba-closo-dodecaboran-9-yl)trifluoroacetamide (8b), N-(1,12-dicarba-closo-dodecaboran-2-yl)benzamide (10a), N-(1,2-dicarba-closo-dodecaboran-9-yl)benzamide (12a), N-(1,2-dicarba-closo-dodecaboran-9-yl)acetamide (12c), N-(1,2-dicarba-closo-dodecaboran-9-yl)formamide (12d), N-(1,2-dicarba-closo-dodecaboran-3-yl)benzamide (13a), N,N'-(1,7-dicarba-closo-dodecaboran-9,10-diyl)dibenzamide (15a), and N,N'-(1,7-dicarba-closo-dodecaboran-9,10-diyl)bis(trifluoroacetamide) (15b) have been established through X-ray single-crystal diffraction studies.
International Institute of Nano and Molecular Medicine, School of Medicine, University of Missouri, 1514 Research Park Drive, Columbia, Missouri 65211-3450, USA.
Yulia
Y
Sevryugina
Richard L
RL
Julius
M Frederick
MF
Hawthorne
D000577:Amides / Q000138:chemical synthesis* / Q000737:chemistry; D001880:Boranes / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D018360:Crystallography, X-Ray; D007455:Iodine / Q000737:chemistry*; D008958:Models, Molecular; D010165:Palladium / Q000737:chemistry*
D000577:Amides; D001880:Boranes; D010165:Palladium; D007455:Iodine