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1alpha(OH)D5 is a good candidate for in vivo chemoprevention studies. It may mediate its action by inducing expression of VDR and of TGF-beta1, as is seen in other systems.

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A multikilogram-scale synthesis of l-lyxonolactone-2,3-O-isopropylidene is reported. It proceeds efficiently from an optimized, large-scale, aqueous bromine oxidation of d-ribose to d-ribonolactone including a one-pot isopropylidene formation, and subsequent conversion of the d-ribonolactone-2,3-O-isopropylidene to l-lyxonolactone-2,3-O-isopropylidene via the derived C5-mesylate and intramolecular relactonization of the product of aqueous potassium hydroxide cleavage of the d-ribonolactone ring. The inversion of configuration at the C4-chiral center is understood in terms of an intermediating C4−C5-epoxide. The overall process is noteworthy for its operational simplicity, stereochemical integrity, and use of inexpensive chemicals.

ChemInform Abstract The trimethylsilyl enol ethers (I) react with hydroxy(mesyloxy or tosyloxy)iodobenzene (II) to give the α-sulfonyloxycarbonyl compounds (III).