New Phenylglycine‐Derived Primary Amine Organocatalysts for the Preparation of Optically Active Warfarin

In this work we present new, fully synthetic phenylglycine‐derived primary amine organocatalysts useful for the one‐step preparation of optically active warfarin, an important anticoagulant. Both enantiomeric forms of the catalysts are equally available and can be prepared by robust procedures without recourse to chromatographic purification. Together with a co‐catalyst, particularly acetic acid or 2,4‐dinitrophenol, they can furnish warfarin in approximately 80 % ee and represent inexpensive alternatives to other primary amine organocatalysts such as the chiral diamines and Cinchona‐derived primary amines.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) Whereas chiral diamines and Cinchona‐derived primary amines have been the traditional organocatalysts for the preparation of warfarin, we want to introduce a new, fully synthetic phenylglycine derivative, equally available in both enantiomeric forms. This organocatalyst may be perceived as a type of primary amine analogue of the Jørgensen/Hayashi diarylprolinol.