[Studies on the syntheses of the hypermodified nucleosides of phenylalanine transfer ribonucleic acids].

This review highlights the first total synthesis of (alpha S, beta S)-beta-hydroxywybutosine, the identity of which was established with fluorescent nucleoside isolated from rat liver tRNA(Phe). Three general prerequisites for the synthesis of the target are emphasized: construction of new 9-beta-D-ribofuranosyl-3-methylpurines; the first syntheses of optically active gamma-aryl-alpha,beta-unsaturated amino acids; and a new method for hydrogenolysis of glycols through their cyclic carbonates to give the gamma-aryl-beta-hydroxy amino acid derivatives. The mechanism for the formation of cyclic carbonates from reactions of glycols with (COCl)2 and highly selective preparation of the cyclic oxalates are also described.