Nitrones and dialkyl cyclopropane-1,1-dicarboxylates undergo smooth reaction in the
presence of ytterbium(III) triflate to form tetrahydro-1,2-oxazines with a high degree
of regio- and stereocontrol. A three-component protocol has also been developed wherein
the nitrone is generated in situ from an aldehyde and a hydroxylamine. The reactions
are often high yielding with broad substrate scope. The multicomponent nature of the
reaction makes it amenable to the synthesis of compound libraries and also allows
for highly convergent strategies to be developed in target-oriented synthesis.
cycloadditions - nitrones - tetrahydro-1,2-oxazines - cyclopropanes - hydroxylamines