Highly Diastereoselective [3+2] Cycloadditions between Nonracemic p-Tolylsulfinimines and Iminoesters: An Efficient Entry to Enantiopure Imidazolidines and Vicinal Diaminoalcohols
作者:Alma Viso、Roberto Fernández de la Pradilla、Ana García、Carlos Guerrero-Strachan、Marta Alonso、Mariola Tortosa、Aida Flores、Martín Martínez-Ripoll、Isabel Fonseca、Isabelle André、Ana Rodríguez
DOI:10.1002/chem.200204674
日期:2003.6.16
highly diastereoselective process with opposite stereochemistry. Subsequent transformations of the imidazolidines including oxidative, reductive, and hydrolytic processes that provide easy access to vicinal diaminoalcohols have been explored. Among these, reductive cleavage of the aminal with LiAlH4 is an extremely efficient and general reaction for the synthesis of enantiopure N-sulfinyl-N'-benzyldiaminoalcohols
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.