Synthesis of enantiopure vicinal diaminoesters and ketopiperazines from N-sulfinylimidazolidines
作者:Alma Viso、Roberto Fernández de la Pradilla、Aída Flores、Ana García
DOI:10.1016/j.tet.2007.05.062
日期:2007.8
A short and efficientsynthesis of mono- and bicyclic ketopiperazines bearing methoxycarbonyl substituents is described. The route entails selective protection and solvolysis of N-sulfinylimidazolidines to provide vicinal diaminoesters with the nitrogen atoms suitably differentiated. Then, an N-acylation/cyclization protocol renders the ketopiperazines. In addition a diastereoselective route to an
Fine-Tuned Aminal Cleavage: A Concise Route to Differentially Protected Enantiopure <i>s</i><i>yn</i>-α,β-Diamino Esters
作者:Alma Viso、Roberto Fernández de la Pradilla、María L. López-Rodríguez、Ana García、Aida Flores、Marta Alonso
DOI:10.1021/jo035613j
日期:2004.3.1
A survey of routes for aminal cleavage of N-sulfinylimidazolidines has been carried out, and selective conditions to cleave the aminal moiety while preserving the sulfinamide group unaltered have been found. Thus, the treatment of enantiopure N-sulfinylimidazolidines with aqueous H3PO4 in THF affords enantiopure N-sulfinyldiamino esters in excellent yields, while the presence of MeOH as cosolvent allows for the simultaneous removal of the sulfinamide group and aminal cleavage. The behavior of these substrates in a variety of chemical transformations has been explored.