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1‐(α‐Aminobenzyl)‐2‐naphthol: A New Chiral Auxiliary for the Synthesis of Enantiopure α‐Aminophosphonic Acids
Author(s) -
Metlushka Kirill E.,
Kashemirov Boris A.,
Zheltukhin Viktor F.,
Sadkova Dilyara N.,
Büchner Bernd,
Hess Christian,
Kataeva Olga N.,
McKenna Charles E.,
Alfonsov Vladimir A.
Publication year - 2009
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.200802540
Subject(s) - enantiopure drug , diastereomer , chemistry , 2 naphthol , toluene , trifluoroacetic acid , chiral auxiliary , crystallization , solvent , organic chemistry , stereochemistry , enantioselective synthesis , catalysis
Ooh Betti! A new diastereoselective synthesis of α‐aminophosphonates has been developed based on the reaction of trialkyl phosphites with chiral imines derived from ( R )‐ or ( S )‐1‐(α‐aminobenzyl)‐2‐naphthol (Betti base; see scheme, X=H, CH 3 , or Br). The reaction proceeds with high diastereoselectivity. Treatment with HCl results in the formation of the desired α‐aminophosphonic acids.A new diastereoselective synthesis of α‐aminophosphonates has been developed, based on the reaction, in the presence of trifluoroacetic acid, of trialkyl phosphites with chiral imines derived from ( R )‐ or ( S )‐1‐(α‐aminobenzyl)‐2‐naphthol. The reaction proceeds at room temperature in toluene with high diastereoselectivity. The major diastereomer can be separated by crystallization from an appropriate solvent. The relative configuration of both chiral centers of the major diastereomer was determined by single‐crystal X‐ray structure analysis. The desired α‐aminophosphonic acids can be obtained in enantiopure form by treatment of the corresponding diastereomers with HCl.