Hydroaluminierungsreaktionen mit dem sperrigen Dialkylaluminiumhydrid [(Me3Si)2HC]2Al‐H ‐ Unterdrückung von Folgereaktionen

Hydroalumination Reactions Employing the Bulky Dialkylaluminum Hydride [(Me3Si)2HC]2Al‐H ‐ Prevention of Secondary Reactions Usually, the hydroalumination of alkynes results in secondary reactions under release of the corresponding trialkylaluminum compounds. In contrast, the monoaddition products of R2Al‐H to C≡C triple bonds [R2Al‐(R′)C=C(R″)‐H] could be isolated in high yields now by employing the bulky dialkylaluminum hydride [(Me3Si)2HC]2Al‐H (1). This is shown here by two reactions starting with a monoalkyne (Me3C‐C≡C‐C6H5) and a dialkyne (Me3C‐C≡C‐C6H4‐C≡C‐CMe3). Both products have the aluminium atoms attached to those carbon atoms of the C=C double bonds which are in the α‐position with respect to the phenyl groups. The configuration of the alkenyl groups verifies the cis‐addition of the Al‐H bonds in all cases.