Efficient syntheses of both enantiomers of a spirodiamine diester from (l)- and (d)-aspartic acid are described. The key transformation was the conversion of Boc-protected tert-butyl aspartate into the derived aldehyde, two-directional Horner-Wadsworth-Emmons olefination, hydrogenation, and selective acid-catalyzed Boc-deprotection and spirocyclization. An alternative, two-directional approach to derivatives of 1,7-diazaspiro[5.5]undecane is described.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.