Photocatalysed addition of alcohols to 5-substituted 2,5-dihydrofuran-2-ones: novel synthesis of (3′R)-2′,3′-dideoxy-3′-hydroxymethyl nucleosides

Methanol and propan-2-ol add in a regiospecific and highly stereocontrolled fashion to 5-substituted 2,5-dihydrofuran-2-ones (butenolides) under irradiation. The photoadducts with methanol have been converted into a number of (3′R)-2′,3′-dideoxy-3′-hydroxymethyl nucleosides.