合成路线1

A practical synthetic approach to lodenosine has been developed: Acylation of the chiral carbinol (I) with 4-methylbenzoyl chloride (II) and pyridine in dichloromethane gives the ester (III), which is diastereoselectively hydrogenated with H2 over Pd/C in ethyl acetate to yield the tetrahydrofuranone (IV). Surprisingly, the diastereoselectivity of this reaction depends on the hydrogen pressure: while at 40 psi it is very poor, at 10 psi it increases to 98%. The reduction of lactone (IV) with red-Al and 2-hydroxypyridine in THF at -30 C affords the lactol (V), which is treated with Ac2O and catalytic concentrated H2SO4 to provide the acetate ester (VI). Reaction of compound (VI) with HBr in AcOH gives the bromo derivative (VII), which is condensed with N6-benzoyl adenine (VIII) by means of NaH in refluxing THF to give the acylated adenosine derivative (IX). Finally, this compound is deprotected with NaOMe in refluxing methanol.