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On the Regio‐ and Stereoselective Synthesis of Aminocyclitols from Cyclitol Epoxides: The Effect of Li as a Chelating Agent
Author(s) -
Serrano Pedro,
Llebaria Amadeu,
Vázquez Jordi,
de Pablo Joan,
Anglada Josep M.,
Delgado Antonio
Publication year - 2005
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.200401270
Subject(s) - stereoselectivity , cyclitol , chemistry , chelation , stereochemistry , botany , organic chemistry , biology , catalysis , biochemistry , inositol , receptor
Experimental and theoretical studies on the influence of Li ions on the regio‐ and the stereoselectivity of the reaction of cyclitol epoxides with nitrogen nucleophiles have been carried out. Model studies with NaN 3 as a nucleophile in the absence of Li ions predict a mixture of C1 and C2 regioadducts. The inclusion of two Li ions as a chelating agent favours the operation of a low populated “all‐axial” conformation leading ultimately to the C1 adducts. In all cases, the results can be rationalised by geometric and energetic considerations of the corresponding transition states. Predictions of the theoretical calculations are in good agreement with the experimental results using primary and secondary amines as nucleophiles, and thus confirm the validity of this study.