Reaction of quadricyclane with fluorinated sulfur-containing compounds

2,2,4,4-Tetrakis(trifluoromethyl)-1,3-dithietane (1) reacts with quadricyclane (2) without a catalyst at ambient or elevated temperature, giving the corresponding cycloadduct, 3-thia-4,4-bis(trifluoromethyl)tricyclo[5.2.1.02,5]non-7-ene (3) in 74% yield. Similar reaction of 2,2,4,4-tetrafluoro-1,3-dithietane (4) at elevated temperature results in the formation of 3-thia-4,4-difuorotricyclo[5.2.1.02,5]non-7-ene (5a) along with two other byproducts. Both (n-C4F9S)2 and [(CF3)2CFS]2 react with 2 upon heating (90–100 °C) giving the corresponding nortricyclanes 9a,b and 11a,b in high yield. The reactions of CH3SO2Cl or CF3SO2Cl and 2 proceed at ambient temperature leading to mixture of isomeric nortricyclanes 13a,b and 15a,b. Reactions of quadricyclane reported here are apparently initiated by a single-electron transfer from quadricyclane to neutral substrates, the first such observed for an alkane.