Gold Colloids Immobilized Cobalt Complexes for Kinetic Resolution

Significance

The gold colloids immobilized cobalt salen complex 3 was prepared for the hydrolytic kinetic resolution (HKR) of epoxides. Thus, a chiral salen ligand 2 was incorporated onto n-octanethiolate-protected gold colloids 1 via an exchange reaction in CH₂Cl₂. The resulting colloids were treated with Co(OAc)₂×H₂O and TfOH under atmospheric conditions to give the [(salen)Co(III)] complex immobilized on gold colloids. The HKR of racemic hexene-1-oxide with water in the presence of 3 proceeded at 20 ˚C to afford a mixture of unreacted hexene-1-oxide with >99.9% ee and 1,2-hexene glycol (k _rel = 180).