Abstract: The reduction of 9-cyanoanthracene by two equivalents of potassium in liquid ammonis was shown to yield the 9-cyanoanthracene dianion, whereas 1-naphtho- and benzonitrile gave the cyanodihydroaryl anions corresponding to the protonation of nitrile dianions at a position para to the cyano group. The 9-cyanoanthracene dianion underwent the same transformation in the presence of a stronger protonating agent, methasol. According to C-13 NMR spectral data of the generated specks, the cyano group extracts the negative charge from the pi-electronic system: ca 0.20:0.25 e in the case of the 9-cyanoanthracene dianion and ca 0.14:0.17 e in the case of cyanodihydroaryl anions. These estimations and the general NMR pattern of pi-charge distribution in all the anionic species under investigation are in accordance with data from quantum molecular orbital calculations at the PM3 and INDO levels, being reflected by the fairly good linear relationships between the changes of ring carbon chemical shifts on going to the anionic species from the respective neutral precursors on the one hand and the calculated pi-charges on the other. The para-orienting effect of the cyano group in the protonation of nitrile dianions is discussed in terms of the pi-charge distribution in the starting dianion and the tendency to form a most stable cyanodihydroaryl anion isomer.

Cite: Bilkis I.I. , Vaganova T.A. , Panteleeva E.V. , Salnikov G.E. , Tananakin A.P. , Mamatyuk V.I. , Shteingarts V.D.
REDUCTIVE ALKYLATION OF ARENES .5. ANIONIC PRODUCTS OF THE 2-ELECTRON REDUCTION OF AROMATIC NITRILES IN LIQUID-AMMONIA
Journal of Physical Organic Chemistry. 1994. V.7. N3. P.153-161. DOI: 10.1002/poc.610070307 WOS Scopus РИНЦ

Dates:

Published print:

Mar 1, 1994

Identifiers:

Web of science	WOS:A1994NE88700005
Scopus	2-s2.0-84985446392
Elibrary	31003764
OpenAlex	W2004960239

Altmetrics: