Di-2,2,2-trifluoro-1-(9-anthryl)ethyl fumarate, an easy starting point for the enantioselective preparation of trans-cyclohexene-4,5-dicarboxylate derivatives by Diels–Alder reaction

Di-2,2,2-trifluoro-1-(9-anthryl)ethyl fumarate has been synthesized from fumaric acid and enantiopure Pirkle alcohol. The Diels–Alder reaction with different dienes employing different reaction conditions was assayed, with high diastereomeric excesses obtained. The structure and geometry of the cycloadducts was analyzed by NMR, molecular mechanics and X-ray diffraction. Hydrolysis made it possible to obtain the enantioenriched trans-cyclohexene-4,5-dicarboxylate derivatives and allow us to recover chiral auxiliary.

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Di-2,2,2-trifluoro-1-(9-anthryl)ethyl fumarateC36H22F6O4Ee = 98%[α]D20 = −80 (c 1.0, CHCl3)Source of chirality: enantiopure reactantAbsolute configuration: (11R,11′R)

Di-[(R)-1-(9-anthryl)-2,2,2-trifluoroethyl](13S,14S)-4,5-dimethylcyclo-4-ene-1,2-dicarboxylateC41H28F6O4Ee = 82%[α]D20 = −62 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (11R,13S,14S,11′R)

Di-[(R)-1-(9-anthryl)-2,2,2-trifluoroethyl](13S,14S,15R,18S)-bicyclo[2.2.2]oct-5-ene-2,3- dicarboxylateC42H30F6O4Ee = 95%[α]D20 = −95 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (11R,13S,14S,15R,18S,11′R)

Di-[(R)-1-(9-anthryl)-2,2,2-trifluoroethyl](13S,14S)-4-methylcyclo-4-ene-1,2-dicarboxylateC41H30F6O4Ee = 90%[α]D20 = −80 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (11R,13S,14S,11′R)

Di-[(R)-1-(9-anthryl)-2,2,2-trifluoroethyl](13S,14S)-4,5-dimethylcyclo-4-ene-1,2-dicarboxylateC42H32F6O4Ee = 90%[α]D20 = −86 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (11R,13S,14S,11′R)