Cross metathesis of the readily available dimethyl 2-vinylcycloropane-1,1-dicarboxylate with a variety of olefins gave divergent access to new donor–acceptor cyclopropanes bearing a π-donor alkenyl substituent. The synthetic utility of these cyclopropanes was shown by their participation in cycloaddition reactions with nitrones to yield the anticipated tetrahydro-1,2-oxazines. Hydrogenation yielded the alkyl-substituted adducts which would be more difficult to access via other means.
Key words
heterocycles - cycloaddition - cyclopropanes - metathesis - ruthenium