Nucleophilic Attack on Iodonium Ion Intermediate. "Real" Regiochemistry of the Iodo Azide Adduct of 1-Phenylcyclohexene and of Its Dehydrohalogenation Product

Article abstract of DOI:10.1021/jo00280a016

The regiochemistry of the anti iodo azide adduct (IAA) of 1-phenylcyclohexene (1), originally reported as 3, was reexamined and proposed to be the reversed one 4 on the basis of its dehydrohalogenation to an unsaturated compound, which was supposed to be the azido olefin 8.Structural data on the anti iodo isocyanate adduct of 1 (5) prompted us to further verify the regiochemistry of the IAA.Comparison of NMR data (¹H and ¹³C) of the IAA with corresponding ones of analogous compounds of proved structures and the absence of any coupling in the ¹⁵N NMR of the IAA led us to reverse further the regiochemistry of the IAA to the original one 3.The dehydrohalogenation product of the IAA was proven to be different from 8 and was unequivocally shown to be the isomeric azido olefin 14.The formation of 14 from 3 (IAA) was rationalized through the initial formation of the azido olefin 16, followed by a <3,3> sigmatropic rearrangement to the more stable isomeric 14.