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Walphos versus Biferrocene-Based Walphos Analogues in the Asymmetric Hydrogenation of Alkenes and Ketones.

ABSTRACT: Two representative Walphos analogues with an achiral 2,2?-biferrocenediyl backbone were synthesized. These diphosphine ligands were tested in the rhodium-catalyzed asymmetric hydrogenation of several alkenes and in the ruthenium-catalyzed hydrogenation of two ketones. The results were compared with those previously obtained on using biferrocene ligands with a C₂-symmetric 2,2?-biferrocenediyl backbone as well as with those obtained with Walphos ligands. The application of one newly synthesized ligand in the hydrogenation of 2-methylcinnamic acid gave (R)-2-methyl-3-phenylpropanoic acid with full conversion and with 92% ee. The same ligand was used to transform 2,4-pentanedione quantitatively and diastereoselectively into (S,S)-2,4-pentanediol with 98% ee.

SUBMITTER: Zirakzadeh A

PROVIDER: S-EPMC4006446 | biostudies-literature | 2014 Apr

REPOSITORIES: biostudies-literature

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Walphos versus Biferrocene-Based Walphos Analogues in the Asymmetric Hydrogenation of Alkenes and Ketones.

Zirakzadeh Afrooz A Groß Manuela A MA Wang Yaping Y Mereiter Kurt K Weissensteiner Walter W

Organometallics 20140409 8

Two representative Walphos analogues with an achiral 2,2″-biferrocenediyl backbone were synthesized. These diphosphine ligands were tested in the rhodium-catalyzed asymmetric hydrogenation of several alkenes and in the ruthenium-catalyzed hydrogenation of two ketones. The results were compared with those previously obtained on using biferrocene ligands with a <i>C</i><sub>2</sub>-symmetric 2,2″-biferrocenediyl backbone as well as with those obtained with Walphos ligands. The application of one n ...[more]

PMID: 24795493

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