Sulfur derivatives of 6,8-dioxabicyclo[3.2.1]octanes related to a number of natural
products have been synthesized by the click hydrothiolation (AIBN or UV irradiation)
of 7-methylene-6,8-dioxabicyclo[3.2.1]octanes, assembled from acetylene and ketones
in a one-pot transition-metal-free synthetic operation. An unusual feature of this
free-radical reaction is that it is accelerated in the presence of bases due to involvement
of the latter in a competition between the thiol addition and proton-catalyzed isomerization
of the starting bicyclooctanes.
Key words
6,8-dioxabicyclo[3.2.1]octanes - thiols - vinyl ethers - hydrothiolation
