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Enantioselective Synthesis of Distorted π‐Extended Chiral Triptycenes Consisting of Three Distinct Aromatic Rings by Rhodium‐Catalyzed [2+2+2] Cycloaddition
Author(s) -
Aida Yukimasa,
Shibata Yu,
Tanaka Ken
Publication year - 2020
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.201905519
Subject(s) - enantioselective synthesis , rhodium , cycloaddition , chemistry , aromatization , cationic polymerization , alkene , stereochemistry , catalysis , carbocation , medicinal chemistry , organic chemistry
The enantioselective synthesis of distorted π‐extended chiral triptycenes, consisting of three distinct aromatic rings, has been achieved with high ee value of 87 % by the cationic rhodium(I)/segphos complex‐catalyzed enantioselective [2+2+2] cycloaddition of 2,2′‐di(prop‐1‐yn‐1‐yl)‐5,5′‐bis(trifluoromethyl)‐1,1′‐biphenyl with 6‐methoxy‐1,2‐dihydronaphthalene followed by the diastereoselective Diels–Alder reaction and aromatization. Demethoxy derivatives were also synthesized by the C−O bond cleavage. In this synthesis, the use of the electron‐deficient diyne and the electron‐rich alkene is crucial to suppress the undesired strain‐relieving carbocation rearrangement and stabilize the distorted triptycene structure.