Separation of planar chiral ferrocene derivatives on β-cyclodextrin-based polymer supports prepared via ring-opening metathesis graft-polymerization

Syntheses and Crystal Structures of Ferrocenoindenes

“…Starting from 2-ferrocenylbenzoic acid (1), 2-ferrocenylbenzoyl chloride was prepared using PCl 5 and cyclized by intramolecular Friedel-Crafts acylation using AlCl 3 to give ferroceno[2,3-a]inden-1-one (2), a planar chiral compound, as a racemate (Scheme 1) [7,13]. Separation of the two enantiomers by HPLC on a β-cyclodextrin-derived chiral column has been reported [13].…”

“…Separation of the two enantiomers by HPLC on a β-cyclodextrin-derived chiral column has been reported [13]. Several synthetic routes to ferroceno [2,3a]indene (3) have been disclosed: (1) reduction of 2 with LiAlH 4 to diastereomeric ferroceno[2,3-a]inden-1-ols, subsequent formation of a cationic complex, and reduction with Na/NH 3 [7]; or (2) direct hydrogenation of 2 [7].…”

“…By analogy, 6-iodoferroceno[2,3-a]inden-1-one (6) was accessible from 5-iodo-2-ferrocenylbenzoic acid (5) [13]. This compound was used for a Sonogashira-Hagihara coupling [13].…”

“…This compound was used for a Sonogashira-Hagihara coupling [13]. A Wittig bromomethylenation gave the new 3-(bromomethylene)-6-iodoferroceno-[1,2-a]indene (7) in acceptable yield.…”

“…Melting points were determined on a Kofler hot-plate microscope and are uncorrected. The synthesis and the spectroscopic data of 2-ferrocenylbenzoic acid (1) [7,17], ferroceno[2,3-a]inden-1-one (2) [7,17], ferroceno[1,2-a]indene (3) [7], 2-ferrocenyl-5-iodobenzoic acid (5) [13], 6-iodoferroceno[2,3-a]inden-1-one (6) [13], and 3-ferrocenyl-2-naphthoic acid (8) [18] have been reported elsewhere.…”