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1,4‐Dialkynylbutatrienes: Synthesis, Stability, and Perspectives in the Chemistry of carbo ‐Benzenes
Author(s) -
Maraval Valérie,
Leroyer Léo,
Harano Aya,
Barthes Cécile,
Saquet Alix,
Duhayon Carine,
Shinmyozu Teruo,
Chauvin Remi
Publication year - 2011
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.201002769
Subject(s) - chemistry , conjugated system , benzene , metathesis , salt metathesis reaction , electrochemistry , stereochemistry , medicinal chemistry , organic chemistry , polymerization , electrode , polymer
The π‐electron‐rich C 8 ‐conjugated sequence of 1,4‐dialkynylbutatrienes is identified as a fragile and fascinating motif occurring in carbo ‐benzene derivatives, and in Diederich’s 1,4‐bis(arylethynyl)‐ or 1,4‐bis(triisopropylsilylethynyl)butatriene “capped” representatives, in particular, in tetraalkynylbutatriene. The family of symmetrical 1,4‐dialkynylbutatrienes (ECC)RCCCCR(CCE) is extended to functional caps (E=H, CH 3 , CCPh, CPhCHBr, or CPhCBr 2 ) with non‐alkynyl substituents at the sp 2 vertices (R=Ph or CF 3 ). The targets were selected for their potential in appealing retrosynthetic routes to carbo ‐benzenes, in which the aromatic C 18 macrocycle would be directly generated by sequential metathesis or reductive coupling processes. The functional 1,4‐dialkynylbutrienes were synthesized by either classical methods used for the preparation of generic butatrienes (R′Li/CuX‐mediated reductive coupling of gem ‐dihaloenynes or SnCl 2 /HCl‐mediated reduction of 3,6‐dioxy‐octa‐1,4,7‐triyne precursors). Their spectroscopic and electrochemical properties are compared and analyzed on the basis of the relative extent of total conjugation.