Xanthates as synthetic equivalents of oxyacyl radicals: access to lactones under tin-free conditions.
In addition to their utility in Barton-McCombie deoxygenations, xanthates can engage in 5-exo-trig radical cyclizations to afford lactones after oxidative workup. In this paper, we describe a tin-free protocol that provides direct access to lactones via hydrolysis of labile thioketal intermediates. Analysis of several systems of varying complexity reveals that the reaction is most applicable for constrained systems in which the reacting center is prepositioned near the radical-accepting alkene.
Department of Chemistry, University of Victoria, Victoria, BC, Canada V8W 3V6.
Jason A
JA
Davy
Jeremy W
JW
Mason
Benoît
B
Moreau
Jeremy E
JE
Wulff
D003500:Cyclization; D005609:Free Radicals / Q000737:chemistry; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry; D008968:Molecular Conformation; D014970:Xanthines / Q000737:chemistry*
D005609:Free Radicals; D007783:Lactones; D014970:Xanthines