Synthesis of [3]Ferrocenophanes via Samarium Diiodide Promoted Reductive Cyclizations of 1,1‘-Dicinnamoylferrocenes

2000-06-01T00:00:00Z (GMT) by Shean-Jeng Jong Jim-Min Fang
A series of 1,1‘-dicinnamoylferrocenes were converted to the corresponding [3]ferrocenophane diols (4ae) in a stereoselective manner by using samarium diiodide to effect the intramolecular coupling reaction, aldol reaction, and reduction in one-pot operation. The major reaction pathway might be derived from a samarium chelated transition state (IA) having the moieties of s-cis enone and (Z)-enolate. A solid-state structure of such [3]ferrocenophane diol product showed that the cyclopentadienyl groups were in an eclipsed orientation and slightly tilted.