Photolysis of a carbohydrate nitroolefin

Abstract

Irradiation of an acetone solution of cis-6,7,8-trideoxy-1,2:3,4-di-O-isopropylidene-7-C-nitro-α-D-galacto-oct-6-enose (4) with ultraviolet light gives a complex mixture from which the three major products have been isolated: the trans isomer of the nitroolefin 4, cis-6,8-dideoxy-1,2:3,4-di-O-isopropylidene-α-D-galacto-oct-5-enos-7-ulose (5), and the trans isomer of 5. The structures of the compounds were established by spectroscopic methods. Signal assignments in the nuclear magnetic resonance spectra have been made by spin decoupling.