The reaction of the organozinc reagent, produced by the reaction of CH 2 I 2 + Zn(C 2 H 5 ) 2 + glyme in diethylether at 20 °C, regioselectively methylates the N 4 -nitrogen of N 4 -desmethylwyosine-triacetate to give pure wyosine-triacetate in 76% isolated yield; no trace of the isomeric N 5 methylated product is found in the latter reaction. Synthesis of a new congener of Y-nucleoside is also reported for the first time from compound in a high overall yield ...