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Synthesis of enantiopure planar chiral bis‐( para )‐pseudo‐ meta ‐type [2.2]paracyclophanes
Author(s) -
Sawada Risa,
Gon Masayuki,
Nakamura Jun,
Morisaki Yasuhiro,
Chujo Yoshiki
Publication year - 2018
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.23010
Subject(s) - enantiopure drug , diastereomer , chemistry , regioselectivity , enantiomer , planar chirality , stereochemistry , substrate (aquarium) , enantioselective synthesis , organic chemistry , catalysis , oceanography , geology
Abstract A new type of planar chiral ( R p )‐ and ( S p )‐4,7,12,15‐tetrasubstituted [2.2]paracyclophanes was prepared from racemic 4,7,12,15‐tetrabromo[2.2]paracyclophane as the starting substrate. Regioselective lithiation and transformations afforded racemic bis‐( para )‐pseudo‐ meta ‐type [2.2]paracyclophane (4,15‐dibromo‐7,12‐dihydroxy[2.2]paracyclophane). Its optical resolution was performed by the diastereomer method using a chiral camphanoyl group as the chiral auxiliary. The diastereoisomers were readily isolated by simple silica gel column chromatography, and the successive hydrolysis afforded ( R p )‐ and ( S p )‐bis‐( para )‐pseudo‐ meta ‐type [2.2]paracyclophanes (( R p )‐ and ( S p )‐4,15‐dibromo‐7,12‐dihydroxy[2.2]paracyclophanes). They can be used as pseudo‐ meta ‐substituted chiral building blocks.