Scheme 17. Construction of Anti-hypertensive Agents.
Applications
The epoxidation of 6-cyano - 2,2-dimethylchormene 24 with 22 affords 25 that can be converted into anti-hypertensive agents cromakalim and EMD-52692 by reaction with appropriate nitrogen nucleophiles (Scheme 17).
The catalyst 22 has been further utilized for the epoxidation of cis -cinnamic ester in 97% ee and 56% yield that can be converted into taxol side chain by opening of the epoxide with ammonia followed by hydrolysis and protection using (t-BuCO)2O (Scheme 18).
Scheme 18