A new Co(0) complex mediated synthesis of C-glycoside analogues
摘要:
Properly protected glyconolactones, readily available from the parent sugars, react under mild conditions with alpha-bromoacetates in the presence of a soluble Co(0) complex, either in stoichiometric Or substoichiometric amounts, to give a Reformatsky-type addition product to the lactone. The addition product can be Subsequently converted into a variety of compounds: dehydroxylation with triethylsilane in the presence of boron trifluoride affords C-glycosides. (C) 2003 Elsevier Ltd. All rights reserved.
Stereoselective synthesis of α-substituted ulosonic acids by magnesio-reformatsky reactions
作者:René Csuk、Christina Schröder、Claus Krieger
DOI:10.1016/s0040-4020(97)00813-2
日期:1997.9
A new method of homologation of aldonolactones allowing the incorporation of propionate units with excellent chemo- and stereoselectivity is performed by the magnesium-graphite mediated reaction between Oppolzer sultam derived α-halogenated amides and an aldonolactone.
Zinc–silver/graphite mediated Reformatsky-reaction of furanoid aldonolactones with α-bromo-esters allows the synthesis of α-substituted 3-ulosonic acids in high yields.