| Abstract
| - O-Methylephedrine was identified as a very efficient chiral auxiliary for ortho-lithiation reactionsof ferrocenes. (1R,2S)-O-Methylephedrine [CH3NHCH(CH3)CH(Ph)OCH3] was reacted with N-ferrocenylmethyl-N,N,N-trimethylammonium iodide [FcCH2N(CH3)3I; Fc = ferrocenyl] to give(1R,2S)-N-ferrocenylmethyl-O-methylephedrine. Treatment of this compound with t-BuLi in pentanefollowed by quenching with the electrophiles iodine, dibromotetrafluoroethane, chlorodiphenylphosphine or benzophenone gave 2-substituted ferrocenes in 98% de and with the (Rp)-ferroceneconfiguration. Subsequently, the chiral auxiliary could be replaced by systems including dimethylamine, acetate, diaryl- or dialkylphosphines to give a number of enantiopure bifunctional1,2-disubstituted ferrocene derivatives such as (Rp)-N-2-iodo- or (Rp)-N-2-bromoferrocenylmethyldimethylamine or (Rp)-2-acetoxymethyl-1-diphenylphosphinoferrocene. As an application, ferrocenyl diphosphines possessing a planar (Rp)-ferrocene configuration only {1,2-(PPh2)FcCH2PR2, R= Cy, Ph, [3,5-(CF3)2Ph]} were synthesized in three steps from O-methylephedrine and N-ferrocenylmethyl-N,N,N-trimethylammonium iodide in up to 77% overall yield.
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