Desymmetrization of Prochiral Phosphanes Using Derivatives of (−)-Cytisine

• Published in: European journal of organic chemistry Vol. 2004; no. 9; pp. 1894 - 1896
• Main Authors: Johansson, Magnus J., Schwartz, Lennart O., Amedjkouh, Mohamed, Kann, Nina C.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.05.2004; WILEY‐VCH Verlag; Wiley
• Subjects: Asymmetric synthesis; CATALYZED ASYMMETRIC HYDROGENATION; Chemistry; Chemistry, Organic; ENANTIOSELECTIVE HYDROGENATION; Enantioselectivity; LIGANDS; Lithiation; P-CHIRAL DIPHOSPHINES; Phosphanes; PHOSPHINE BORANES; PHOSPHORUS; Physical Sciences; Science & Technology; Sparteine; STRATEGY; enantioselectivity; CATALYZED ASYMMETRIC HYDROGENATION; PHOSPHINE BORANES; PHOSPHORUS; asymmetric synthesis; LIGANDS; STRATEGY; ENANTIOSELECTIVE HYDROGENATION; P-CHIRAL DIPHOSPHINES; sparteine; lithiation; phosphanes
• ISSN: 1434-193X; 1099-0690; 1099-0690
• DOI: 10.1002/ejoc.200400006

Historically, (−)‐sparteine·sec‐BuLi has been used to desymmetrize prochiral phosphanes. In this report, derivatives of an alkaloid extracted from the seeds of Laburnum anagyroides have been utilized to mimic (+)‐sparteine, which is not readily available. In several cases, the enantioselectivities achieved with the (+)‐sparteine surrogates outperformed (−)‐sparteine itself in the deprotonation of alkyl‐substituted (as well as aryl‐substituted) prochiral phosphane derivatives. In addition, use of these surrogates allows a new methodology for a chiral switch in phosphorus chemistry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)