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Preparation of C 3 ‐Symmetric Homochiral syn ‐Trisnorbornabenzenes through Regioselective Cyclotrimerization of Enantiopure Iodonorbornenes
Author(s) -
Reza A. F. G. Masud,
Higashibayashi Shuhei,
Sakurai Hidehiro
Publication year - 2009
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.200900132
Subject(s) - enantiopure drug , regioselectivity , palladium , chemistry , nanoclusters , trifluoromethanesulfonate , catalysis , combinatorial chemistry , molecule , yield (engineering) , stereochemistry , enantioselective synthesis , organic chemistry , materials science , metallurgy
C 3 ‐symmetric homochiral (−)‐ syn ‐trisoxonorbornabenzene 1 possessing a rigid cup‐shaped structure was synthesized through a novel regioselective cyclotrimerization of enantiopure iodonorbornenes catalyzed by palladium nanoclusters. The yield of the cyclotrimerization was dependent on the stability of the palladium clusters, which was ascertained from the appearance and TEM images of the reaction mixtures. The efficient preparation of (−)‐ syn ‐ 1 was established in short steps, including the newly developed cyclotrimerization reaction. The thus‐prepared homochiral (−)‐ syn ‐ 1 can serve as a key intermediate for the synthesis of C 3 ‐symmetric homochiral cup‐shaped molecules with a helical arrangement of substituents. Introduction of several types of substituents was well demonstrated through palladium‐catalyzed coupling reactions with the corresponding phosphate and triflate of (−)‐ syn ‐ 1 .