C-6 allylated pyranosides for the synthesis of complex oxygenated tetrahydrofurans

Article abstract of DOI:10.1016/S0040-4020(97)00282-2

The iodoetherification of C6 allylated D-pyranosides containing an allylic benzyloxy substituent, and their acyclic 5-hexen-,1,2,4-triol analogs were performed. Pyranosides of R configuration at the allylic ether gave exclusively a syn,syn-2,5-dialkyl-3-oxy-tetrahydrofuran which is primed for elaboration into several classes of naturally occurring THF's. By comparison, the stereoselectivity for the non-pyranoside derivative was much lower. In the S series, the bias was opposite for the pyranoside vs. the non-pyranoside substrates, but the selectivity in both cases was low.