Total Syntheses of 2,4-Diamino-2,4-dideoxy-L-arabinose and 2,4-Diamino-2,4-dideoxy-L-ribose

摘要

This methodology exploiting the use of readily available pyrrole-based reagent N-(tert-butoxy-carbonyl)-2-(tert-butyldiniethylsiloxy)pyrrole (5) and enan-tioenriched (93-95% ee) L-serinal 6 can easily lead to densely functionalized pyrrolidines, 15 and 16, representatives of a scantly investigated subclass of five-membered ring azasugars. When the lactam intermediates 7 and 8 are used as starting materials, both syntheses proceeded through a uniform protocol of only four reactions (51% and 48% overall yields), comprising shortening of the seven-carbon backbone by two atoms (7/8 → 11/12) and remarkably selective intramolecular aldehyde animation (11/12 → 13/14).