Regiospecific and stereoselective conversion of ribonucleosides to 3′-deoxynucleosides. A high yield three-stage synthesis of cordycepin from adenosine.

Treatment of 2′,3′-anhydroadenosine (obtained² in 92% yield from adenosine) with lithium triethylborohydride (or deuteride) gave cordycepin (or its 3′($\text{R}$)-deuterio derivative) in ≈90% overall yields with no 2′-deoxy isomer detected.