Electrophilic azidation of 2-deoxy-aldono-1,5-lactones: an alternative route to 2-azido-2-deoxy-aldopyranoses
Abstract
Electrophilic azidation of tri-O-benzyl-2-deoxy-D-galactono-1,5-lactone 3 with triisopropylphenylsulfonyl azide, followed by selective reduction with diisobutylaluminium hydride, yielded tri-O-benzyl-2-azido-2-deoxy-D-galactopyranose 5 as the sole product in 80% yield, while the same sequence of reactions with the 2-deoxy-glucono-1,5-lactone derivative 8 afforded only tri-O-benzyl-2-azido-2-deoxy-D-mannopyranose 10 in 65% yield.