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Synthese und NMR‐Spektren von Nonafulven sowie Vergleich mit 10‐Phenylnonafulven
Author(s) -
Furrer Jürg,
Bönzli Peter,
Frey Alfred,
Neuenschwander Markus,
Engel Peter
Publication year - 1987
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19870700327
Subject(s) - chemistry , mndo , yield (engineering) , planarity testing , ring (chemistry) , nmr spectra database , molecule , stereochemistry , computational chemistry , crystallography , spectral line , organic chemistry , materials science , physics , astronomy , metallurgy
Synthesis and NMR Spectra of Nonafulvene and Comparison with 10‐Phenylnonafulvene Experimental procedures for the reaction of cis , cis , cis , trans ‐cyclononatetraenide ( ccct ‐CNT − ; see 4 ) with bromomethyl acetate ( 1a , R = H, X = Br) to give (cyclononatetraenyl)methyl acetate ( 5a ; 84% yield) as well as for the base‐induced elimination of HOAc from 5a to give nonafulvene ( 6a ; 44% yield) are described. Spectroscopic as well as chemical evidence for 6a and 6b is presented. An approximate high‐field‐NMR analysis of 6a and 6b has been completed. The results are in favour of a fast interconversion of the type 6A⇄6B ( Scheme 4 ), and supported by the MNDO‐optimised geometry of 6a . The first X‐ray analysis of a cyclononatetraene (i.e. of 5b ) has been accomplished: 5b is a polyolefinic molecule with largely alternating bond lengths and with a nine‐membered ring deviating strongly from planarity.