Synthesis 2014; 46(11): 1475-1480
DOI: 10.1055/s-0033-1340955
paper
© Georg Thieme Verlag Stuttgart · New York

Solvent-Free Synthesis of a Secondary N-Benzhydrylamine as a Chiral Reagent for Asymmetric Deprotonation of Bicyclic N-Benzylamino Ketones

Aneta Nodzewska*
Institute of Chemistry, University of Bialystok, Hurtowa 1, 15-399 Bialystok, Poland   Fax: +48(85)7470113   eMail: annodz@uwb.edu.pl
,
Katarzyna Sidorowicz
Institute of Chemistry, University of Bialystok, Hurtowa 1, 15-399 Bialystok, Poland   Fax: +48(85)7470113   eMail: annodz@uwb.edu.pl
,
Michal Sienkiewicz
Institute of Chemistry, University of Bialystok, Hurtowa 1, 15-399 Bialystok, Poland   Fax: +48(85)7470113   eMail: annodz@uwb.edu.pl
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Publikationsverlauf

Received: 20. Dezember 2013

Accepted after revision: 17. Februar 2014

Publikationsdatum:
24. März 2014 (online)


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Abstract

Several chiral secondary N-benzhydrylamines were synthesized in good yields (68–92%) without racemization by the direct alkylation of amines with benzhydryl chloride under solvent-free conditions. Using the solvent-free conditions (R)-N-benzhydryl-1-phenylethylamine was obtained with the highest yield (92%), purified on ion-exchange resin, and converted to its hydrochloride salt. The resulting chiral amine hydrochloride was transformed into lithium amide/lithium chloride mixture used in asymmetric deprotonations of N-benzyl analogues of tropinone and granatanone followed by aldol reactions giving products in high ­diastereomeric purities (up to 96%) and enantiomeric excesses of 77 to 96%.

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