Synthesis and characterization of enantiopure planar–chiral phosphorus‐linked diferrocenes. Issue 3 (25th February 2021)

• Record Type: Journal Article
• Authors: Honegger, Philipp; Roller, Alexander; Widhalm, Michael
• Is Part Of: Acta crystallographica. Volume 77:Issue 3(2021)
• Page Start: 152
• Page End: 160
• Publication Date: 2021-02-25
• Subjects: crystal structure -- metal organic -- three‐dimensional structure -- ferrocene -- phosphine sulfide -- chirality -- planar chirality; Crystallography -- Periodicals; Crystals -- Periodicals; 548.3
• DOI: 10.1107/S2053229621001996
• Languages: English
• ISSNs: 2053-2296

Abstract

Abstract : Six new homochiral diferrocenyl derivatives have been synthesized, one of which is purely planar–chiral. Even if the two diferrocene subunits are identical, they are distinguished due to their positions relative to the substituents at the phosphorous prochiral centre. Abstract : In the course of an ongoing synthetic project on cyclic diferrocenylphosphines, we obtained a group of planar–chiral diferrocenyl compounds useful as precursors for subsequent cyclization. Here we report the crystal structures of two symmetric compounds [(Fc A )2 (Ph)P], one of which contains four stereogenic centres (two C chiral and two planar chiral centres), i.e. 1, 1′‐(phenylphosphanediyl)bis{(2 S p )‐2‐[(1 R )‐1‐(acetyloxy)ethyl]ferrocene}, [Fe2 (C5 H5 )2 (C24 H25 O4 P)], and the other phosphine sulfide is a purely planar–chiral compound (two planar chiral centres), i.e. bis[(2 S p )‐‐2‐ethenylferrocen‐1‐yl]phenylphosphane sulfide, [Fe2 (C5 H5 )2 (C20 H17 PS)]. Owing to the stereocentres present, reactions performed on [(Fc A )2 (Ph)P]‐type compounds strongly favour one ferrocene unit over the other due to diastereoselectivity. Furthermore, we present four related structures where the ferrocene units are not identical [(Fc A )(Fc B )(Ph)P]. These are {(2 S p )‐2‐[(1 R )‐1‐(acetyloxy)ethyl]ferrocen‐1‐yl}[(2 S p )‐2‐ethenylferrocen‐1‐yl]phenyl‐( S )‐phosphine sulfide, [Fe2 (C5 H5 )2 (C22 H21 O2 PS)], [(2 S p )‐2‐ethenylferrocen‐1‐yl]{(2 S p )‐2‐[(1 R )‐1‐hydroxyethyl]ferrocen‐1‐yl}phenyl‐( S )‐phosphine sulfide, [Fe2 (C5 H5 )2 (C20 H19 OPS)], {(2 S p )‐2‐[(1 R )‐1‐(acetyloxy)ethyl]ferrocen‐1‐yl}{(2 S p )‐2‐[(1 R )‐1‐hydroxyethyl]ferrocen‐1‐yl}phenyl‐( R )‐phosphine sulfide, [Fe2 (C5 H5 )2 (C22 H23 O3 PS)], and {(2 S p )‐2‐[(1 R )‐1‐benzylamino)ethyl]ferrocen‐1‐yl}[(2 S p )‐2‐ethenylferrocen‐1‐yl]phenyl‐( S )‐phosphine sulfide, [Fe2 (C5 H5 )2 (C27 H26 NPS)]. All of the structures are accessible in one step from known precursors.