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Asymmetric synthesis of highly functionalized tetrahydropyrans via a one-pot organocatalytic Michael/Henry/ketalization sequence.

ABSTRACT: A diastereo- and enantioselective Michael/Henry/ketalization sequence to functionalized tetrahydropyrans is described. The multicomponent cascade reaction uses acetylacetone or ?-keto esters, ?-nitrostyrenes, and alkynyl aldehydes as substrates affording tetrahydropyrans with five contiguous stereocenters. Employing a bifunctional quinine-based squaramide organocatalyst, the title compounds are obtained in moderate to good yields (27-80%), excellent enantiomeric excesses (93-99% ee), and high diastereomeric ratios (dr > 20:1) after one crystallization.

SUBMITTER: Hahn R

PROVIDER: S-EPMC4700516 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature

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Asymmetric synthesis of highly functionalized tetrahydropyrans via a one-pot organocatalytic Michael/Henry/ketalization sequence.

Hahn Robert R Raabe Gerhard G Enders Dieter D

Organic letters 20140627 14

A diastereo- and enantioselective Michael/Henry/ketalization sequence to functionalized tetrahydropyrans is described. The multicomponent cascade reaction uses acetylacetone or β-keto esters, β-nitrostyrenes, and alkynyl aldehydes as substrates affording tetrahydropyrans with five contiguous stereocenters. Employing a bifunctional quinine-based squaramide organocatalyst, the title compounds are obtained in moderate to good yields (27-80%), excellent enantiomeric excesses (93-99% ee), and high di ...[more]

PMID: 24971998

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