Synthesis 2005(16): 2782-2786  
DOI: 10.1055/s-2005-872111
PAPER
© Georg Thieme Verlag Stuttgart · New York

Practical Synthesis of Enantiomerically Pure 2-(Diphenylphosphanyl)ferro­cene Carboxylic Acid

Bernhard Breit*, Daniel Breuninger
Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany
Fax: +49(761)2038715; e-Mail: bernhard.breit@organik.chemie.uni-freiburg.de;
Further Information

Publication History

Received 6 April 2005
Publication Date:
04 August 2005 (online)

Abstract

A practical synthesis of both enantiomers of ortho-diphenylphosphanylferrocene carboxylic acid (o-DPPFA) starting from ferrocene is described. Key steps include the synthesis of the racemic title compound from ferrocene in two steps followed by resolution by way of diastereomeric ester formation with glucose diacetonide. The synthesis allows for preparation of gram quantities of both optical antipodes of o-DPPFA (3) in good yields and enantiomerically pure form (>99% ee).

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The quality of both s-BuLi and chlorodiphenylphosphine was crucial to obtain good results. Older solutions of s-BuLi often led to dramatically decreased yields (ca. 30%).