Ruthenium-Catalyzed Nucleophilic Ring-Opening Reactions of a 3-Aza-2-oxabicyclo[2.2.1]hept-5-ene with Alcohols

Ruthenium-catalyzed nucleophilic ring-opening reactions of a 3-aza-2-oxabicyclo[2.2.1]hept-5-ene with alcohols were investigated. When a neutral ruthenium(II) catalyst, Cp*RuCl(COD), was used in MeOH, the trans-1,2-ring opened product was formed as the only regio- and stereoisomer. On the other hand, when a cationic ruthenium(II) catalyst, [CpRu(CH(3)CN)(3)]PF(6), was used in MeOH, the cis-1,2-ring opened product was formed exclusively. Moderate to excellent stereoselectivity (70:30 to 100:0) was observed with various alcohols.