Stereoselectivities in the reactions of α-d-hexopyranosid-4-uloses with diazomethane
作者:Ken-Ichi Sato、Juji Yoshimura
DOI:10.1016/s0008-6215(00)80685-0
日期:1982.5
Abstract The stereoselectivities in the reactions of diazomethane with various α- d -hexopyranosid-4-uloses are compared with those in Grignard reactions. The results support the hypothesis that the stereoselectivity of the diazomethanereaction is mainly controlled by the attractive, electrostatic force between the diazomethyl cation and a neighbouring, axial oxygen or the axial lone-pair electrons
The reagent combination, ruthenium dioxide/sodium periodate/benzyltriethyl ammonium chloride in dichloromethane/aqueous bicarbonate buffer simultaneously oxidises alcohol functions in the sugar ring and glycosyl H-phosphonates to yield keto-glycosyl phosphates. These can be coupled to the respective nucleoside diphosphates to render biosynthetically relevant sugar metabolites and derivatives thereof, useful for further investigation of the polysaccharide biosynthesis in bacteria and plants. (C) 1999 Elsevier Science Ltd. All rights reserved.
TWO COMPLEMENTARY METHODS FOR INTRODUCTION OF<i>gem</i>-DIMETHYL GROUP IN HEXOPYRANOSIDE RING
Hexopyranosides having a gem-dimethyl group in the pyranose ring were synthesized By reductive cleavage of spiro-cyclopropane derivatives and By addition of methyl cuprates to methyl-branched enolone derivatives.