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Novel Multichiral Diols and Diamines by Highly Stereoselective Pinacol Coupling of Planar Chiral [2.2]Paracyclophane Derivatives
Author(s) -
Sergeeva Elena V.,
Rozenberg Valeria I.,
Antonov Dmitrii Yu.,
Vorontsov Evgenii V.,
Starikova Zoya A.,
Fedyanin Ivan V.,
Hopf Henning
Publication year - 2005
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200500413
Subject(s) - pinacol , stereoselectivity , chemistry , diamine , enantioselective synthesis , diol , ketone , stereochemistry , enantiopure drug , diastereomer , organic chemistry , catalysis
Abstract The TiCl 4 /Zn‐mediated intermolecular pinacol coupling of the planar chiral carbonyl compounds [2.2]paracyclophane‐4‐carbaldehyde, 4‐acetyl[2.2]paracyclophane (ketone) and the four regioisomeric 5‐, 7‐, 12‐ and 13‐methoxy[2.2]paracyclophane‐4‐carbaldehydes as well as the p TosOH–Zn/Cu‐promoted coupling of their N‐substituted imines is described. Coupling of the enantiomerically pure substrates (most of carbonyl compounds and all imines) occurs stereoselectively giving rise to diastereomerically pure 1,2‐diols and 1,2‐diamines. Racemic aldehydes and ketone react with different degrees of stereoselectivity (depending on the substituents in certain positions) and produce one to three diastereomers. 7‐Methoxy[2.2]paracyclophane‐4‐carbaldehyde undergoes a tandem pinacol coupling–pinacol rearrangement to yield bis‐(7‐methoxy[2.2]paracyclophane‐4‐yl)acetaldehyde. Coupling of the racemic imines produces a mixture of single racemic D , L ‐diamine and single meso ‐diamine in each case. The stereoselective formation of the asymmetric centres is governed by the planar chiral [2.2]paracyclophanyl moiety. The techniques elaborated are extended to the intramolecular coupling of [2.2]paracyclophane‐4,13‐dicarbaldehyde and its bis‐N‐phenylimine, resulting in stereoselective formation of the chiral triply‐bridged diol and exclusive formation of the meso ‐diamine. X‐Ray investigations of several diols and diamines have been carried out and the structural features of these derivatives are discussed.