The reactivity of O-acylglycosyl halides. Part VIII. Exchange reactions of O-acetylglycosyl bromides with lithium bromide in acetone

Abstract

Radioactive tracer methods have been used to measure the rates of exchange between lithium bromide and a series of O-acetylglycosyl bromides in anhydrous acetone. The results indicate that the exchange reaction is second order even when there is evidence of neighbouring-group participation for 1,2-trans-halides. Steric effects resulting from varying the configuration of the sugar influence the reactivity in a similar manner to that found in the S_N1 solvolytic reactions of these halides.