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Highly Diastereoselective [3+2] Cycloadditions between Nonracemic p ‐Tolylsulfinimines and Iminoesters: An Efficient Entry to Enantiopure Imidazolidines and Vicinal Diaminoalcohols
Author(s) -
Viso Alma,
Fernández de la Pradilla Roberto,
García Ana,
GuerreroStrachan Carlos,
Alonso Marta,
Tortosa Mariola,
Flores Aida,
MartínezRipoll Martín,
Fonseca Isabel,
André Isabelle,
Rodríguez Ana
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200204674
Subject(s) - enantiopure drug , vicinal , chemistry , stereochemistry , cycloaddition , aminal , enantioselective synthesis , organic chemistry , catalysis
A new procedure for the asymmetric synthesis of imidazolidines and vicinal diamines is reported. The 1,3‐dipolar cycloaddition between nonracemic p ‐tolylsulfinimines and azomethine ylides generated in situ from α ‐iminoesters and LDA produces N ‐sulfinylimidazolidines with a high degree of stereocontrol. In contrast, the presence of Lewis acids promotes formation of the cycloadducts through a 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 LiAlH 4 is an extremely efficient and general reaction for the synthesis of enantiopure N ‐sulfinyl‐ N′ ‐benzyldiaminoalcohols.