Synthesis of 2'-cyclohexenylnucleosides and corresponding CeNA building blocks.

A cyclohexene ring has similar structural properties and conformational behavior to a saturated five-membered furanose ring. In particular, it has good hydrolytic stability. Cyclohexenylnucleosides have been utilized in antiviral drug design, and some nucleosides and oligonucleotides based on the cyclohexene system have been developed. For further investigation of these modified nucleosides and oligonucleotides, synthesis of the chiral cyclohexenylnucleosides in high enantiomeric excess and in bulk quantities is necessary. This unit describes the complete synthesis of four enantiomerically pure 5'-hydroxy-4'-hydroxymethyl-2'-cyclohexenylnucleosides (thymine, cytosine, guanine, and adenine) and the four corresponding N-protected 4'-(monomethoxytrityl)oxymethyl cyclohexenyl nucleic acids (CeNA) building blocks. The chirality of these compounds is 1'S, 4'R, and 5'S.