Synthesis of Tetrahydro‐1,2‐oxazines and Pyrrolidines via Cycloadditions of Donor–Acceptor Cyclobutanes and Nitrosoarenes

Abstract

Abstract During efforts to expand the scope of Lewis‐acid‐catalyzed [4+2] cycloaddition between donor–acceptor cyclobutanes and nitrosoarenes, an unexpected formation of pyrrolidine products was discovered when 50 mol‐% of MgI 2 was used as a Lewis acid. It was also observed that the electronics of the nitrosoarene and judicious selection of the Lewis acid catalyst have a profound effect on the regioselectivity of the reaction.