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Towards Stapling of Helical Alleno‐Acetylene Oligomers – Synthesis of an Enantiopure Bis(ethynylvinylidene)‐Substituted Cyclohexadeca‐1,3,9,11‐tetrayne
Author(s) -
Müller I.E. Sophie,
Bernet Bruno,
Dengiz Cagatay,
Schweizer W. Bernd,
Diederich François
Publication year - 2014
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.201301529
Subject(s) - enantiopure drug , chemistry , diacetylene , metathesis , dimer , acetylene , stereochemistry , ring closing metathesis , trimer , oxidative coupling of methane , negishi coupling , enantioselective synthesis , organic chemistry , polymer , polymerization , catalysis
We are interested in developing strategies to bridge (“staple”) enantiomerically pure acyclic alleno‐acetylenic oligomers to enhance their conformational preferences for helical secondary structures, which are postulated to be at the origin of their exceptional chiroptical properties. We found that ring‐closing metathesis (RCM), which has been used for the stapling of peptide helices, failed with an acyclic alleno‐acetylene dimer decorated with lateral olefinic side chains. Instead, enyne RCM to an enantiomerically pure dienyne occurred. We switched to the introduction of diacetylene‐containing bridges and report here the 15‐step synthesis of a moderately strained, enantiomerically pure cyclohexa‐1,3,9,11‐tetrayne with an oxidative acetylenic coupling in the key step. The chiroptical properties of the new compounds are discussed.