Ring opening reactions of thiiranes by alkoxo- and aryloxo-gold(I) complexes

Abstract

Alkoxo- and aryloxo-gold(I) complexes [Au(OR)L] [R = CH(CF₃)₂, L = PPh₃ 1a or PCy₃ 1b; R = Ph, L = PPh₃ 1c, PCy₃ 1d or PMe₃ 1e] smoothly reacted with ethylene sulfide to give the corresponding 2-(alkoxy- or -aryloxy)ethylsulfanylgold(I) complexes [Au(SCH₂CH₂OR)L] 2 at room temperature. Similar treatments of 1a–1e with propylene sulfide, isobutylene sulfide, or styrene sulfide selectively cleaved the less hindered C–S bond of thiiranes to give corresponding 2-(alkoxy- or -aryloxy)ethylsulfanylgold(I) complexes. Reactions of 1a with cis- and trans-2-butene sulfide gave syn- and anti-[Au(SCHMeCHMeOR)L], respectively, suggesting a mechanism involving an S_N2 type trans addition of alkoxogold(I) complexes toward thiiranes.