Reactions of Pentafluorosulfanyl Isocyanate and Isothiocyanate

Abstract The purification of pentafluorosulfanyl isocyanate ( 1 ) is rendered less difficult by isolation of the intermediate (pentafluorosulfanyl)carbamoyl fluoride, while pentafluorosulfanyl isothiocyanate ( 2 ) can easily be prepared by the reaction of dichloro(pentafluorosulfanylimino)methane with phosphorus pentasulfide in boiling toluene. Both 1 and 2 react readily with alcohols to give urethanes 3a – e and thiourethane 4 , respectively, and with thiols to give thiolurethanes 5a, b and dithiourethane 6 . With amines 1 and 2 form a variety of substituted ureas 7, 8a – e, 10a – c , and thiourea 9 . Of particular interest is the reaction of 1 with tertiary amines which yields zwitterionic derivatives 11a, b . N ‐(Pentafluorosulfanyl)imine derivatives 12a – e, 13a, b, 14 are prepared from the reactions of 1 or 2 with aldehydes and N,N ‐disubstituted amides. The reaction of 1 with acetylacetone gives the N ‐(pentafluorosulfanyl)amide of diacetoacetic acid ( 16 ), which in solution is observed in both the keto form and two distinct enol forms. With trimethyl orthoformate 1 gives not only the expected N ‐methyl‐ N ‐(pentafluorosulfanyl)urethane 18 but also the classical addition product 2,2,2‐trimethoxy‐ N ‐(pentafluorosulfanyl)acetamide ( 17 ).