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Chiral Polyaryl Cyclophanes
Author(s) -
Pascal Robert A.,
Dudnikov Andrey,
Love LeaAnn A.,
Geng Xin,
Dougherty Kelly J.,
Mague Joel T.,
Kraml Christina M.,
Byrne Neal
Publication year - 2017
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201700732
Subject(s) - racemization , chemistry , cyclophane , enantiomer , aryl , circular dichroism , phosphine , tris , stereochemistry , optical rotation , crystallography , organic chemistry , crystal structure , alkyl , catalysis , biochemistry
A series of propeller‐shaped, C 3 ‐symmetric cyclophanes have been synthesized by the macrocyclization of 1,3,5‐trimercaptobenzene ( 12 ) with either a tris[ o ‐(halomethyl)aryl]phosphine (e.g. 11 ) or a tris[ o ‐(halomethyl)aryl]benzene (e.g. 24 ). Two phosphine‐capped cyclophanes ( 5 and 6 ) were prepared in this way; they proved to be configurationally stable, and both were resolved into pure enantiomers by supercritical fluid chromatography on chiral supports. Compound 6 , in particular, displayed a large specific rotation ([ α ] D ≈ 800) and strong circular dichroism. The one triarylbenzene‐capped cyclophane ( 9 ) that was made possessed a modest barrier to racemization (Δ G rac ‡ = 15.7 kcal/mol). Computational studies of the trends in optical rotation for this class of compounds as well as the pathway for the racemization of 9 are also reported.