Synthesis of novel 3'-C-methyl-4'-thio apionucleosides via highly enantioselective elaboration of quaternary carbon by [3,3]-sigmatropic rearrangement

Article abstract of DOI:10.1016/S0040-4039(98)02324-7

Asymmetric synthesis of 3'-C-methyl-4'-thio apionucleosides was accomplished from the chiral intermediate 6. The chirality of quaternary carbon of the key intermediate 6 was transferred from the chirality of secondary allylic alcohol 5 via [3,3]-sigmatropic Claisen rearrangement with high enantiomeric excess (estimated to be 98.5% ee). The thioglycosyl intermediate 11 was condensed with silylated N⁴-benzoylcytosine followed by deprotection to give the desired nucleoside 12.