Aminodimethylalanes (R(1)R(2)NAlMe(2)) as useful synthetic precursors of aminoalane difluorides using trimethyltin fluoride: Crystal structures of (2,6-i-Pr2C6H3)N(SiMe(3))AlMe(2) and (2,6-i-Pr2C6H3)N(SiMe(3))AlF2

Aminodimethylalanes R(1)R(2)NAlMe(2) (R(1) = 2,6-i-Pr2C6H3, 2,6-Me(2)C(6)H(3); R(2) = SiMe(3), Si(i-Pr)Me(2), Si(t-Bu)Me(2), Si(2,4,6-Me(3)C(6)H(2))Me(2)) are prepared in high yield via reaction of the respective amine R(1)R(2)NH with trimethylaluminum in n-hexane. Further reaction of (2,6-i-Pr2C6H3)N(SiMe(3))AlMe(2) with 2 equiv of trimethyltin fluoride in toluene affords the aminoalane difluoride (2,6-i-Pr2C6H3)N(SiMe(3))AlF2. An X-ray structural determination of (2,6-i-Pr2C6H3)N(SiMe(3))AlMe(2) shows it to be dimeric with bridging methyl and terminal amino groups. The aminoalane difluoride (2,6-i-Pr2C6H3)N(SiMe(3))AlF2 is trimeric with a six-membered alternating aluminum-fluorine ring. Terminal fluorine atoms are located above and below the ring. Reactions of aminoalanes R(1)R(2)NAlMe(2) with 2 equiv of trimethyltin fluoride in THF yield the monomeric THF adducts R(1)R(2)NAlF(2) . THF.