Synthesis of a novel trisubstituted cyclobutane nucleoside analogue. Unexpected C4-C3 ring contractions in related reactions

Article abstract of DOI:10.1016/S0040-4020(97)00266-4

Nucleoside analogue 7 was obtained by nuclceophilic substitution between adenine and mesylate 5b. On the other hand the same reaction starting from its isomer 5a did not work and led to the surprising ring contraction products 8a and 8b. Another unexpected ring contraction leading to 15 was pointed out in the course of preparation of the deuteriated compounds 5a' and 5a''. Position of deuterium in products 8a' and 8b' or 8a'' and 8b'' issued from reactions with 5a' or 5a'' gave useful mechanistic informations on this reaction.