SYNTHESIS OF TETRAHYDRO-1,2-OXAZINES BY THE CYCLOADDITION OF NITRONES WITH CYCLOPROPANES

摘要

One aspect of the present invention relates to a method of preparing tetrahydro-1,2­ oxazines comprising the step of combining a nitrone and a cyclopropane in the presence of a Lewis acid. Another aspect of the present invention relates to a method of preparing a tetrahydro-1,2-oxazine, comprising the step of combining an aldehyde and a hydroxylamine in the presence of a Lewis acid to generate a nitrone in situ, then admixing a cyclopropane. Another aspect of the present invention relates to converting a tetrahydro-l,2-oxazine to a pyrrolidine comprising the step of admixing a tetrahydro-1,2-oxazine and a reducing agent.