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

摘要

A variety of substituted 5-alkyl(aryl)idene- and 5-[io-doalkyl(aryl)idene]-lH-pyrrol-2(5H)-ones were readily prepared with good yields under very mild reaction conditions by the iodocy-clization of (2Z,4E)-dienamides and (Z)-alk-2-en-4-ynamides with iodine monochloride. 3-Ylidene-isoindolin-l-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.The iodocyclization of heteroatoms such as oxygen, nitrogen, and sulfur with tethered alkynes has proved to be an effective method for the preparation of a wide variety of heterocyclic ring systems. Important heterocycles such as furans, pyrroles, thiophenes, indoles, quinolines, and others have been accessed using this protocol.