Synthesis of 5-Metalla-Spiro[4.5]Heterodecenes by [1,4]-Cycloaddition Reaction of Group 13 Diyls with 1,2-Diketones

Monovalent group 13 diyls are versatile reagents in oxidative addition reactions. We report here [1,4]-cycloaddition reactions of β-diketiminate-substituted LM (M = Al, Ga, In, Tl; L HC[C(Me)NDipp]2, Dipp 2,6-iPr2C6H3) with various 1,2-diketones to give 5-metalla-spiro[4.5]heterodecenes 1, 4–6, and 8–10, respectively. In contrast, the reaction LTl acenaphthenequinone gave [2,3]-cycloaddition product 7, Tl remaining +1 oxidation state. Compound 1 also reacted a second equivalent butanedione as well benzaldehyde aldol-type corresponding α,β-hydroxyketones 2 3, while reductive activation benzene ring was observed benzil two equivalents LAl 1,4-aluminacyclohex-2,4-dien 12. addition, L’BCl2 (L HC[C(Me)NC6F5]2) one presence KC8 5-bora-spiro[4.5]heterodecene 13, whereas hydroboration L’BH2 (14), which obtained from L-selectride, failed saturated 5-bora-spiro[4.5]heterodecane.