Efficient Regio- and Stereoselective Synthesis of 5-Alkyl(aryl)idene- and 5-[Iodoalkyl(aryl)idene]-1H-pyrrol-2(5H)-ones via Electrophilic Cyclization

A variety of substituted 5-alkyl(aryl)idene- and 5-[iodoalkyl(aryl)idene]-1H-pyrrol-2(5H)-ones were readily prepared with good yields under very mild reaction conditions by the iodocyclization of (2Z,4E)-dienamides and (Z)-alk-2-en-4-ynamides with iodine monochloride. 3-Ylidene-isoindolin-1-ones were also synthesized in moderate to good yields under the same conditions. The methodology proceeded with total regioselectivity in all cases and was applied to the synthesis of new unsaturated lactam compounds.