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Synthesis and characterization of enantiopure planar–chiral phosphorus‐linked diferrocenes
Author(s) -
Honegger Philipp,
Roller Alexander,
Widhalm Michael
Publication year - 2021
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229621001996
Subject(s) - ferrocene , phosphine , enantiopure drug , chemistry , stereocenter , sulfide , medicinal chemistry , stereochemistry , organic chemistry , catalysis , enantioselective synthesis , electrode , electrochemistry
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}, [Fe 2 (C 5 H 5 ) 2 (C 24 H 25 O 4 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, [Fe 2 (C 5 H 5 ) 2 (C 20 H 17 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, [Fe 2 (C 5 H 5 ) 2 (C 22 H 21 O 2 PS)], [(2 S p )‐2‐ethenylferrocen‐1‐yl]{(2 S p )‐2‐[(1 R )‐1‐hydroxyethyl]ferrocen‐1‐yl}phenyl‐( S )‐phosphine sulfide, [Fe 2 (C 5 H 5 ) 2 (C 20 H 19 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, [Fe 2 (C 5 H 5 ) 2 (C 22 H 23 O 3 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, [Fe 2 (C 5 H 5 ) 2 (C 27 H 26 NPS)]. All of the structures are accessible in one step from known precursors.