An efficient and scalable synthesis of substituted phenanthrenequinones by intramolecular Friedel-Crafts reaction of imidazolides.

An efficient synthesis of 9,10-phenanthrenequinones is described. The two carbonyl groups were introduced by an orthoselective intermolecular Friedel-Crafts reaction of 3-methoxyphenol with ethyl chlorooxoacetate. The formation of a biaryl bond by Suzuki-Miyaura coupling reaction, followed by the hydrolysis of the ester, gave a biaryloxoacetic acid.

Asymmetric synthesis of a selective endothelin A receptor antagonist.

An asymmetric synthesis of a selective endothelin A receptor antagonist 1b is described. Asymmetric conjugate addition of aryllithium derived from 18 to the chiral oxazoline 17 followed by hydrolysis afforded 15 in 96% ee via purification as (S)-(-)-1-phenylethylamine salt. Pd(OAc)(2)/dppf (1,1'-bis(diphenylphosphino)ferrocene) catalyzed carbonylation followed by chemoselective addition of aryllithium derived from 23 which gave ketone 24.