Pergamon Tetrahedron: Asymmetry, Vol. 7, No. 5, pp. 1419-1430,1996 Copyright© 1996ElsevierScience Ltd Printedin GreatBritain. All rights reserved 0957-4166/96$15.00 + 0.00 S0957-4166(96)00159-0 Synthesis of Phosphinoferrocenyloxazolines. New Ligands for Asymmetric Catalysis Christopher J. Richards* and Andrew W. Mulvaney Departmentof Chemistry, University of Wales, Cardiff, PO Box 912, Cardiff, CF1 3TB, UK. Abstract: Condensation of [3-hydroxy alcohols with ferrocenyl chloride gave the corresponding amides which were dehydrated to give ferrocenyl oxazolines in good overall yield. Subsequent lithiation with n-BuLl in the presence of TMEDA and addition of PPh2C1 led to the isolation of (S)-(s)-ipr-phosferrox and (S)-(S)-Me-phosferrox ligands 1 and 2. Their corresponding diastereoisomers, (S)-(R)JPr-phosferrox and (S)-(R)-Me-phosferrox 3 and 4 were obtained via the intermediacy of removable trimethylsilyl blocking groups. The CD spectra of 1 - 4 and their parent ferrocenyl oxazolines 9 and 10 were obtained. Copyright © 1996 Elsevier Science Ltd Introduction Ferrocene-derived ligands utilise the planar chirality that results when the ferrocene nucleus contains two different substituents attached to a cyclopentadienyl ring. 1 Of the examples known, most are derived from N,N-dimethyl-1-ferrocenylethylamine as this can be obtained enantiomerically pure by classical resolution2 or asymmetric synthesis) In contrast, oxazoline ligands exploit the tetrahedral stereocentres inherent in the amino acids from which they are derived. On coordination, their 4-substituent lies proximal to the metal thereby influencing the stereoselectivity of catalysed reactions. 4 In particular, phosphinoaryloxazolines containing electronically unsymmetrical nitrogen and phosphorous coordinating groups, have proved to be very successful ligands for asymmetric allylic substitution reactions. 5 Thus attaching oxazolines to an appropriate ferrocene nucleus has the potential benefits of cooperatively combining the tetrahedral chirality inherent in the oxazoline with the planar chirality of disubstituted ferrocenes. 6 O ?3 Ph2 Ph2 N Me Me N ...... ( Fe~" PPh2 IMe Fe PPh2 Fe Me Fe 1 2 3 4 (S)- (s)-ipr-phos ferrox (S)-(S)-Me-phos ferrox (S)-(R)-ipr-phosferrox (S)-(R)-Me-phosferrox Phosferrox ligands 1419