Synthesis of Some N-Aryl a-Amino Acids Using Diaryliodonium Salts

Abstract

Bis[(3'-methoxycarbonyl)phenyl]iodonium bromide (4a), bis(4'-methoxyphenyl)iodonium iodide (4b) and bis(4'-acetamidophenyl)iodonium iodide (4c) were employed for the first time in the arylation of a-amino acid methyl esters. Yields of the synthesised products 5, 6 and 7 were good to high. These were then hydrolyzed to the corresponding N-aryl a-amino acids 8 and 9. The chiral integrity of the amino acids was maintained throughout the reaction sequence as confirmed by the synthesis of chiral tripeptide 10 and dipeptides 11. The structures of the new compounds were confirmed by IR, ¹H and ¹³C NMR in addition to CHN microanalysis or high resolution mass spectrometry.