Structure and reactivity studies of the aluminum analogue of Piers' borane [HAl(C 6 F 5 ) 2 ] 3 .

The aluminum analogue of Piers' borane, [HAl(C 6 F 5 ) 2 ] 3 1, is prepared on a gram-scale. Density functional theory (DFT) calculations reveal 1 has a higher fluoride ion affinity (FIA) than Piers' borane, while the Al-H moiety proved to be a strong hydride donor, reacting with alcohol and terminal alkyne to give the corresponding dehydrogenative products 3 and 4. Hydroalumination product 5 was prepared via reaction of 1 with aldehyde. In addition, 1 catalyzes the hydrosilylation of alkynes and alkenes.