Asymmetric synthesis of ferrocenylazido alcohols and their derivatization to novel chiral ferrocenyl-thiazoline ligands with C2-symmetry

The synthesis of previously unreported chiral ferrocenyl-thiazoline ligands is described. (R)-2-Azido-1-ferrocenylethanol 3 and (R,R)-1,1'-bis(2-azido-1-hydroxyethyl)ferrocene 10. available by enantioselective borane reduction of alpha-azidoacetyl ferrocene 1 and 1,1'-bis(2-azidoacetyl)ferrocene 2, respectively. were converted into the corresponding ferrocenyl thiazolines by a three-step sequence invoking catalytic hydrogenation, acylation and cyclization promoted by Lawesson's reagent. New chiral ferrocene-thiazolines with C-2-symmetry were obtained either from (R)-2-azido-1-ferrocenylethanol 3 and diacyl chlorides or from (R,R)-1,1'-bis(2-azido-1-hydroxyethyl)ferrocene 10 and monoacyl chlorides, (C) 2002 Elsevier Science Ltd. All rights reserved.