A variety of 2-deoxy-1-0-diphenoxylphosphoryl-hexopyranoses were generated in situ by a radical 2+ 1 migration of the phosphate group. The structures of the reactive rearrangement products were fully elucidated by NMR spectroscopy. Rate constants for this new rearrangement were determined for a variety of substrates.Introduction. -The radical 2+ 1 migration of acyloxy groups in glycosyl radicals is a well known reaction [I]. Recently, we and Crich and Yao published studies [2] on the hitherto unknown radical rearrangement of diphenoxyphosphoryl groups. As radical precursors, 3,4,6-tri-O -acetyl-2-0 -(diphenoxyphosphoryl)-a -D-glucopyranosyl bromide (1 ; -+ 2, see Scheme I) and 3,5-di-0 -benzoyl-2-0 -(diphenoxyphosphoryl)-D-ribofuranosy1 bromide were examined. The full extent of this new rearrangement has now been demonstrated by studies on other pyranose radical precursors.