A general protocol for functionalization
of glycosyl thiols has
been reported. This protocol is based on a single-electron Ni/photoredox
dual-catalyzed cross coupling between 1-thiosugars and a broad range
of aryl bromides and iodides as well as alkenyl and alkynyl halides.
This base-free method gives access to a series of functionalized thioglycosides
in moderate to excellent yields with a perfect control of the anomeric
configuration. Moreover, it has been shown that this methodology may
be transposed successfully to the continuous-flow photoredox chemistry.