Oligoribonucleotide Synthesis. V. Preparation of 2-O-Tetrahydropyranyl Derivatives of Guanosine and Their Insertion into a General Stepwise Synthesis

The syntheses of N 2 -benzoyl-2′-O-tetrahydropyranylguanosine (5) and its corresponding 5′-O-tri-phenylmethoxyacetyl derivative (6) are described. Compounds 5 and 6 are the protected derivatives of guanosine required for insertion into a phosphotriester synthesis for oligoribonucleotides. Syntheses of GpC and GpG were carried out to illustrate incorporation of 5 and 6 into a sequence.