Two new C-9 protecting groups for the anomeric position of carbohydrates are reported. Methods both for their introduction and removal are described. The C-9-protected compounds are much less polar than the corresponding allyl protected analogues. The new protecting group chemistry has been used to prepare compound 17 en route to a disaccharide analogue of the antibiotic moenomycin A. (C) 1998 Elsevier Science Ltd. All rights reserved.