CAGE-FLUORINATION DURING DEBORONATION OF META-CARBORANES

Reactions of the meta carboranes 1,7-RR'-1,7-C2B10H10 (R, R' = Me; R = Ph, R' = Me; R, R' = Ph; R, R' = 4-FC6H4) with tetrabutylammonium flu oride hydrate (TBAFH) in refluxing tetrahydrofuran gave the correspond ing nido-7,9-RR'-7,9-C2B9H10- salts, The aryl carboranes and TBAFH als o yielded salts of the B-fluorinated anions 10-F-7,9-RR'-7,9-C2B9H9- a nd 3-F-7,9-RR'-7,9-C2B9H9-. The reaction of 1,7-(4-FC6H4)(2)-1,7-C2B10 H10 with TBAFH monitored by F-19 NMR showed cage fluorination occurred during deboronation to give 10-F-7,9-(4-FC6H4)(2)-7,9-C2B9H9-. The la tter anion rearranged spontaneously to 3-F-7,9-(4-FC6H4)(2)-7,9-C2B9H9 - under the reaction conditions. The B-11, C-13, H-1 and F-19 NMR spec tra of the carboranes have been assigned. (C) 1997 Published by Elsevi er Science Ltd.