Total synthesis of (S,S)-isodityrosine

The novel dimeric amino acid isodityrosine 1 has been synthesized by a route which uses a new method of diaryl ether preparation. Nucleophilic addition of a protected tyrosine to cyclohexenone oxide and the Pd(O)-catalyzed coupling of an aryl iodide with a protected iodoalanine derivative are the key steps in this synthesis. This represents one of the first efficient syntheses of this molecule beginning with two naturally-occurring amino acids as inexpensive starting materials (C) 1997 Elsevier Science Ltd.