1,2-Migration in the reactions of ruthenium vinyl carbene with propargyl alcohols

Abstract

Reactions of the ruthenium vinyl carbene complex [Ru{CHC(PPh₃)CH(2-Py)}Cl₂PPh₃]BF₄ (1) with five propargyl alcohols HCCC(OH)R¹R², (R¹ = R² = Ph; R¹ = Ph, R² = CH₃; R¹ = H, R² = Ph; R¹ = H, R² = CH₃; R¹ = CHCH₂, R² = CH₃) have been investigated, which led to the formation of several ten-membered η²-olefin coordinated ruthenacycles [Ru{OCR²CHR¹-η²-CHCHC(PPh₃)CH(2-Py)}Cl₂PPh₃]BF₄ (R¹ = R² = Ph, 2; R¹ = Ph, R² = CH₃, 3; R¹ = H, R² = Ph, 4; R¹ = H, R² = CH₃, 5; R¹ = CHCH₂, R² = CH₃, 6), respectively. In these reactions, insertion of alkynes and intramolecular 1,2-migration of propargyl alcohols were performed in tandem. The results show that the 1,2-migratory preference of the groups is in the order of H > Ph > CH₃. Complexes 2, 3, 5, and 6 were characterized by X-ray diffraction analysis and NMR spectra.