Ring-opening of cyclic ethers by aluminum hydridotriphenylborateElectronic supplementary information (ESI) available: Description of compounds 1-4. CCDC 1530667 and 1530668. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7cc01159h

Molecular aluminum hydride [(L)AlH 2 ] (L = Me 3 TACD) reacted with 2 equiv. of BPh 3 in THF or THP to give the cationic alkoxides [(L)Al(OR)][HBPh 3 ] (R = n Bu, n Pent) by facile ring-opening of the cyclic ethers. The C α -O bond cleavage which involves the isolable intermediate [(L)AlH][HBPh 3 ] is a result of hydride transfer to C α from [HBPh 3 ] − . Ring-opening of THF or THP in the presence of pinacolborane can be catalyzed by a molecular aluminum hydride catalyst [(L)AlH 2 ] 2 (L = Me 3 TACD)/BPh 3 and involves an isolable intermediate [(L)AlH][HBPh 3 ].