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Synthesis and Structures of Cross‐Conjugated Bis‐dehydroannulenes with a Y‐Enediyne Motif and Different π Topologies
Author(s) -
Bandyopadhyay Arkasish,
Varghese Babu,
Hopf Henning,
Sankararaman Sethuraman
Publication year - 2007
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.200601512
Subject(s) - annulene , enediyne , conjugated system , stereochemistry , chemistry , pyrrole , crystal structure , crystallography , organic chemistry , polymer
A synthesis of cross‐conjugated bis‐dehydroannulenes with different topologies of the π electrons by Cu II ‐mediated oxidative coupling of the corresponding terminal acetylenic precursors is reported. In general, of the two possible modes of cyclization, which would yield either a [13]annulene or an [18]annulene, the precursors yielded exclusively the bis‐dehydro[13]annulenes. However, one example of the formation of a bis‐dehydro[18]annulene is also reported. The mode of cyclization to form either the [13]annulene or the [18]annulene is explained on the basis of the conformational preference of the core unit bearing the Y‐enediyne moieties. The structures of the two types of bis‐annulenes have been unequivocally established by means of single‐crystal X‐ray crystallographic analysis.