A Novel Approach to Ferrocenes with Planar Chirality

Abstract

Abstract The 2‐metalation of enantiomerically pure ( S )‐(2‐methoxy‐methylpyrrolidin‐1‐yl)ferrocene FcSMP ( 1 ) with BuLi proceeds with high diastereoselectivity (up to 98% de) to yield the Ph 2 P‐substituted ferrocene ( S,S p )‐ 2a after quenching with Ph 2 PCl. The SMP moiety was removed by heating of 2a at reflux in acetic anhydride to give planar chiral ( S p )‐2‐diphenylphosphanylferrocenylmethyl acetate ( 5 ). The diastereoisomer ( S,R p )‐ 2b was synthesized from 1 by intermediately blocking the primary metalation site with a Me 3 Si group which can be removed afterwards by treatment with KO t Bu in DMSO. Compound 2a was treated with [(C 3 H 5 )PdCl] 2 to give the complex [(C 3 H 5 )Pd· 2a ]PF 6 ( 7 ·PF 6 ). The structure of 7 ·PF 6 was determined by a single‐crystal X‐ray diffraction study and showed 2a to act as a bidentate P,N ‐chelate ligand.