Synthesis of two trisaccharides related to the hepatoprotective phenylethanoids leonoside E and F isolated from Leonurus japonicus Houtt

•Synthesis of two trisaccharides from a single disaccharide minimising protecting group manipulations.•Use of La(OTf)3 in conjunction with N-iodosuccinimide for the activation of thioglycosides.•Use of p-methoxyphenyl glycoside that can be removed selectively from the per-O-acetylated oligosaccharides.

The chemical synthesis of two trisaccharides related to leonoside E and F is reported. The target oligosaccharides were prepared in the form of their p-methoxyphenyl glycosides using a common disaccharide acceptor. All reaction steps were high yielding (>80%) and the stereoselective glycosylations were achieved by activation of the thioglycoside donors using N-iodosuccinimide in the presence of La(OTf)3.

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