Reactivity of Dialumane and "Dialumene" Compounds toward Alkenes.

The reactions of dialumane [L(thf)Al-Al(thf)L] (1, L=[{(2,6-iPr2C6H3)NC(Me)}2](2-)) with stilbene and styrene afforded the oxidation/insertion products [L(thf)Al(CH(Ph)-CH(Ph))AlL] (2) and [L(thf)Al(CH(Ph)-CH2)Al(thf)L] (3), respectively. In the presence of Na metal, precursor 1 reacted with butadienes, possibly through the reduced "dialumene" or the "carbene-like" :AlL species, to yield aluminacyclopentenes [LAl(CH2C(Me)=C(Me)CH2)Na]n (4 a) and [Na(dme)3][LAl(CH2C(Me)=CHCH2)] (4 b, dme=dimethoxyethane) as [1+4] cycloaddition products, as well as the [2+4] cycloaddition product 1,6-dialumina-3,8-cyclodecadiene, [{Na(dme)}2][LAl(CH2C(Me)=C(Me)CH2)2AlL] (5). The possible mechanisms of the cycloaddition reactions were studied by using DFT computations.