4-vinylidene-2-oxazolidinone

N-Tosyl- and N-benzoyl-4-vinylidene-2-oxazolidinones underwent [4 + 2]-cycloaddi-tions with MVK at the enamide double bond to furnish the spiro adducts [154]. 

Furan (and 2,3-dihydrofuran) reacted as a 2jt-component with 4-vinylidene-2-oxazolidinone in a formal inverse electron demand Diels-Alder reaction with concomitant 1,3-sulfonyl migration to furnish a tricyclic product, as depicted below <07CEJ9686>. 

Nishina and Yamamoto have also reported the gold(I)allenes with alcohols [109]. As an example, treatment of a neat mixture of p-tolyl allene and isopropanol with a catalytic 1 1 mixture of (PPh3)AuCl and AgOTf at 30 °C led to isolation of isopropyl )-3-(4-tolyl)-2-propenyl ether in 98% yield (Eq. (12.39)). The protocol was most effective for monosubstituted and 1,3-disubstituted allenes and gave no transfer of chirality for the hydroalkoxylation of 1-phenyl-l,2-butadiene. Horino has reported the gold(I)-catalyzed intermolecular addition of alcohols to the allenyl moiety of 4-vinylidene-2-oxazolidinones [110]. 

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