Metal- and oxidant-free skeletal reorganizing of oxazolidines to access N-Vinylpyrroles

Abstract

Multisubstituted pyrroles are important moieties in biologically active molecules and functional materials. Direct cyclization of propargylamines provides a straightforward approach to build these scaffolds; however, such a method is often hampered by the need for special reactive groups and the difficulty of introducing a vinyl group on the pyrrole ring. Here we report a strategy for the skeletal reorganizing of N-propargyl oxazolidines to access N-vinylpyrroles under metal- and oxidant-free conditions. This novel reaction starts with base-mediated deprotonation/cyclization/isomerization, followed by a ring opening and β-elimination involving cleavage of two C–O bonds. The reaction, with a wide substrate range, is operationally simple and tolerates a variety of functional groups.