1. For a recent review on cation−π cyclization chemistries, see:Snyder, S. A.; Levinson, A. M.InComprehensive Organic Synthesis, 2nd ed.Knochel, P., Molander, G. A., Eds.Elsevier:Amsterdam, 2014; Vol.3,Part 5, pp268–291and references therein.
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3. bRayner, C. M.InOrganosulfur Chemistry: Synthetic Aspects;Page, P., Ed.Academic Press:London, 1995; pp89–131.
4. Thiiranium and Thiirenium Ions Chemistry and Stereochemistry
5. dCapozzi, G.; Modena, G.; Pasquato, L.InThe Chemistry of Sulphenic Acids and Their Derivatives;Patai, S., Ed.John Wiley & Sons Ltd.:West Sussex, 1990; pp403–516.