Convenient synthesis of N2-isobutyryl-2′-O-methyl guanosine by efficient alkylation of O6-trimethylsilylethyl-3′,5′-di-tert-butylsilanediyl guanosine

We present a novel route for the synthesis of N2-isobutyryl-2′-O-methyl guanosine, introducing 3′,5′-di-tert-butylsilyl and O6-trimethylsilylethyl groups as efficient protections during the 2′-O-methylation step with NaH/CH3I. These protections were then removed simultaneously in a single step with TBAF. The eight-step synthesis is easy to perform, employing convenient commercially available reagents; crude mixtures are of satisfying purity, so only three chromatography purifications were required. Title compound was obtained in 25% overall yield from guanosine.