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Asymmetric synthesis of biaryl atropisomers by dynamic resolution on condensation of biaryl aldehydes with (-)-ephedrine or a proline-derived diamine.

ABSTRACT: Atropisomeric biaryl aldehydes undergo diastereoselective condensation with (-)-ephedrine and with a proline-derived diamine, with selectivity highly dependent on solvent, temperature and reaction conditions. Levels of thermodynamic control up to 5:1 may be obtained by heating the diamine with the aldehyde in a sealed tube. Alternatively, crystallisation-induced dynamic transformation allows isolation of a single diastereoisomer in up to 85% yield. Hydrolysis and reduction of the major diastereoisomeric product of the reaction yields atropisomeric biaryls in >99:1 enantiomeric ratios.

SUBMITTER: Bracegirdle A

PROVIDER: S-EPMC2633665 | biostudies-literature | 2008

REPOSITORIES: biostudies-literature

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Asymmetric synthesis of biaryl atropisomers by dynamic resolution on condensation of biaryl aldehydes with (-)-ephedrine or a proline-derived diamine.

Bracegirdle Ann A Clayden Jonathan J Lai Lai Wah LW

Beilstein journal of organic chemistry 20081204

Atropisomeric biaryl aldehydes undergo diastereoselective condensation with (-)-ephedrine and with a proline-derived diamine, with selectivity highly dependent on solvent, temperature and reaction conditions. Levels of thermodynamic control up to 5:1 may be obtained by heating the diamine with the aldehyde in a sealed tube. Alternatively, crystallisation-induced dynamic transformation allows isolation of a single diastereoisomer in up to 85% yield. Hydrolysis and reduction of the major diastereo ...[more]

PMID: 19190743

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