Synthesis of type 2 Lewis antigens via novel regioselective glycosylation of an orthogonally protected lactosamine diol derivative.

The novel and efficient synthesis of type 2 Lewis antigens is reported in this study. The rationally designed lactosamine-3,2′-diol derivative with an orthogonal set of protecting groups is efficiently glycosylated with a benzyl protected 1-thio- l -fucoside donor in a unique regioselective manner to produce Lewis x (Le x ) and Lewis y (Le y ) derivatives in good yields. These derivatives can be prepared not only exclusively but also synchronously by choosing the appropriate reaction temperature and donor–acceptor molar ratio. The Le x derivatives are easily converted into sulfated or non-sulfated Le x bearing a terminal azido functionalized oligo-(ethyleneoxide) linker; the Le y derivative having the same linker can also be prepared, all of which can be further used for the chemical modification of other compounds and materials. [ABSTRACT FROM AUTHOR]