0022-3263/80/1945-3347 $01.00/0 problems inherent in the phosphodiester method. However, only a few examples of the insertion of 5'-terminal phosphate residues in the phosphotriester approach to oligoribonucleotide synthesis" have been published. The native transfer ribonucleic acids (t-RNAs) contain a 5'-terminal phosphate. Consequently, the development of a convenient insertion of 5'-phosphate groups during the synthesis of ...