Allylsilanes in the preparation of 5'-C-hydroxy or bromo alkylthymidines

Article abstract of DOI:10.1016/S0040-4020(99)00246-X

The reaction of 5'-C-thymidine aldehyde with allytrimethylsilane promoted by BF₃:Et₂O lead stereoselectively to 5'-C(S)-allylthymidine which is converted to 5'-C(S)-hydroxyhexylthymidine. 5'-C-(R or S) hydroxypentylthymidine can be obtained by using ω- tertButyldimethylsilyloxyallyltrimethylsilane in the Sakurai reaction. In the same conditions, ω-Bromoallyltrimethylsilane adds to the aldehyde with a complete transposition of the siliranium intermediate and allows the preparation of the 5'-C(S)-bromopentene derivative.