Abnormal Four-Membered Ring Formation in Intramolecular Radicalic Cyclization. High Stability of the Alkyl Radical Substituted with Methylthio and p-Tolylsulfonyl Groups

Abstract
Treatment of 5-iodo-1-(methylthio)-1-(p-tolylsulfonyl)-1-pentene with (n-Bu)3SnH and AIBN gave [(methylthio)(p-tolylsulfonyl)methyl]cyclobutane. This is due to the stability of an intermediary radical attached to methylthio and p-tolylsulfonyl groups.