Tetrahydrofurfuryloxide Derivatives of Alkyl Aluminum Species

Tetrahydrofurfuryl alcohol (H-OTHF) was successfully reacted with a series of aluminum
alkyls (AlR3) to yield compounds of the general formula [R2Al(μ-OTHF)]2 where R = CH3
(1), CH2CH3 (2), and CH2CH(CH3)2 (3). Further, reactivity studies showed that the alkyls
for 1 were easily exchanged, forming compounds of the general formula [Me(OR)Al(μ-OTHF)]2
where OR = OC6H3(Me)2-2,6 (4), OC6H3(CMe3)2-2,6 (5a), and OSi(C6H5)3 (6). For 5a, reflux
temperatures were required to get the full exchange; otherwise the asymmetric derivative
[Me(OR)Al(μ-OTHF)2AlMe2] (5b) was isolated. The bulk powders of 1−6 were found to be in
agreement with the crystal structures on the basis of elemental analyses and multinuclear
solid state NMR studies. Multinuclear solution state NMR studies indicate that the alkyl
OTHF derivatives have cis/trans isomers due to the chiral proton on the OTHF ligand.