A novel approach to unsaturated acyclic nucleoside analogues and the first synthesis of d4T by ring closure metathesis

Novel unsaturated acyclic nucleoside analogues, 1-{1-[1-(hydroxymethyl)prop-2-enyloxy]prop-2-enyl}uracil, 1-{1-[1-(hydroxymethyl)prop-2-enyloxy]prop-2-enyl}thymine and 1-{1-[1-(hydroxymethyl)prop-2-enyloxy]prop-2-enyl}cytosine have been prepared in good yield from uridine and 5-methyluridine by periodate cleavage followed by a double Wittig reaction which introduces two vinyl groups. The thymine derivative underwent ring closure metathesis to give a novel synthesis of d4T.