Intramolecular Oxyamination of Alkenes

Significance

Herein, Michael and Lovick report a highly regioselective and metal-free annulative amino­fluoroacetoxylation of alkenes. Using hypervalent iodine(III) as the oxidant and an excess of Brønsted acid, the authors transformed a variety of sulfonamidoalkenes 1 into five-, six-, and ­seven-membered ring products 2 including the natural product (-)-pseudoconhydrine 3. Interestingly, depending on the alkene substitution (aryl vs. alkyl) and substrate strain either 5-exo (product 4a) or 6-endo (product 4b) selectivity is observed. Intermediacy of an aziridinium ion C is proposed to explain the unusual endo selectivity.