Allyloxy and propargyloxy group migration: role of remote group participation in the synthesis of 5-C-nucleosides and other sugar derivatives.

In 1-deoxy-xylofuranose derivatives possessing a good leaving group at 2-C, participation of allyloxy and propargyloxy substituents at 5-C results in loss of the 2-C substituent and attack of various nucleophiles at 5-C of the oxonium intermediate. Such participation of a benzyloxy or crotyloxy group leads to dioxabicyclo[2.2.1]heptane rings.