Alternative Access to Lactosamine-derived Oxazoline via 2-Ulose Oxime as a Key Intermediate

Lactosamine-derived oxazoline was synthesized via 2-ulose oxime as a key intermediate, in which substituent effects of the acyloxyimino group were investigated. On reduction of the oxime to amino group, p-chlorobenzoyloxime provided a good gluco: manno selectivity of 13: 1. N-Acetyllactosaminyl chloride derived therefrom was readily converted into the oxazoline by AgOTf-promoted cyclization with an 84% yield.