This report describes the first example of palladium-catalyzed ortho-C–H glycosylation/ipso-alkenylation of aryliodides, and the easily accessible glycosyl chlorides are used as a glycosylation reagent. The reaction is compatible with the functional groups of the substrates, and a series of C-aryl glycosides have been synthesized in good to excellent yield and with excellent diastereoselectivity.
Stereocontrolled chemical glycosylation remains a major challenge despite vast efforts reported over many decades and so far still mainly relies on trial and error. Now it is shown that the relative reactivity value (RRV) of thioglycosides is an indicator for revealing stereoselectivities according to four types of acceptors. Mechanistic studies show that the reaction is dominated by two distinct intermediates:
Synthetic studies on glycocinnamoylspermidines. Synthesis of a key intermediate of the diaminohexose moiety: Ethyl p-[4-amino-2-(tert-butoxycarbonyl)amino-2,4,6-trideoxy-α-d-glucopyranosyloxy]cinnamate
作者:Koichi Araki、Hironobu Hashimoto、Juji Yoshimura
DOI:10.1016/0008-6215(82)84035-4
日期:1982.11
Abstract A keysyntheticintermediate for the diaminohexosyloxycinnamate moiety of glycocinnamoylspermidines was synthesized from d -galactose by two routes, via 3,4,6-tri-O-acetyl-2-azido-2-deoxy- d -galactopyranosyl nitrate (20) and via 1,6-anhydro-2-azido-2-deoxy-β- d -galactopyranose (12), in 16 and 22 steps, respectively.