The first carborane triflates: synthesis and reactivity of 1-trifluoromethanesulfonylmethyl- and 1,2-bis(trifluoromethanesulfonylmethyl)-o-carborane.
The first carborane triflates, namely, 1-trifluoromethanesulfonylmethyl-o-carborane (2) and 1,2-bis(trifluoromethanesulfonylmethyl)-o-carborane (7), were obtained in high yields in the reactions of 1-hydroxymethyl-o-carborane (1) or 1,2-bis(hydroxymethyl)-o-carborane (6) with triflic anhydride (Tf2O) in CH2Cl2 in the presence of pyridine. When an excess of pyridine is employed, 1-o-carboranylmethylpyridinium triflate (3), which retains a closo-icosahedral structure, or a pyridinium salt (4) with a zwitterionic nido-dicarbaundecaborate anion are obtained from 1, while the nido compound 8 is formed from 6. The reaction of compound 2 or 7 with excess pyridine also gave 3 or 8, respectively. Compound 2 proved to be a convenient carboranylmethylating agent which reacts with nucleophiles (e.g., potassium phthalimide, PPh3 or KCN) to give the corresponding substitution products N-[(o-carboranyl-1-yl)methyl]phthalimide (9), o-carboranylmethylphosphonium salt 10, and 1-cyanomethyl-o-carborane (11). All compounds were characterized by 1H and 11B NMR spectroscopy. The structures of compounds 4, 7 and 8 were established by X-ray analysis.
Kalinin
V N
VN
A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilova str., Moscow, 119991, Russia. vkalin@ineos.ac.ru
Rys
E G
EG
Tyutyunov
A A
AA
Starikova
Z A
ZA
Korlyukov
A A
AA
Ol'shevskaya
V A
VA
Sung
D D
DD
Ponomaryov
A B
AB
Petrovskii
P V
PV
Hey-Hawkins
E
E
D001896:Boron Compounds / Q000138:chemical synthesis* / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D010797:Phthalimides / Q000737:chemistry / Q000378:metabolism; D011725:Pyridines / Q000737:chemistry / Q000378:metabolism
D001896:Boron Compounds; D010797:Phthalimides; D011725:Pyridines; C037431:phthalimide; C023666:pyridine