Hetero-Diels-Alder reactions opposing 2H-pyrroles to substituted nitrosoalkenes are described. The chemoselectivity and regiospecificity of the reaction are discussed. New fused pyrrolo-[1,5-e]-1,2,4a-oxadiazines and pyrrolo-[1,5-d]-imidazoles-1-oxide structures are reported. (C) 2002 Elsevier Science Ltd. All rights reserved.
Crystal and molecular structure of four compounds resulting from nucleophilic addition of 2H-pyrroles to dimethyl acetylene-dicarboxylate, methyl propiolate and phenyl isocyanate