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Notizen: Das Tribenzylidenmethan‐Dianion
Author(s) -
Wilhelm Dieter,
Clark Timothy,
von Ragué Schleyer Paul,
Buckl Klaus,
Boche Gernot
Publication year - 1983
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19831160441
Subject(s) - chemistry , mndo , trimethylenemethane , propene , conjugated system , computational chemistry , chemical shift , charge density , superacid , medicinal chemistry , organic chemistry , molecule , cycloaddition , catalysis , polymer , physics , quantum mechanics
The Tribenzylidenemethane Dianion In contrast to the reported difficulties in preparing the tetraphenyl‐substituted cyclobutadienyl dianion 3 ‐2K, dilithiation of 2‐benzyl‐1,3‐diphenyl‐1‐propene ( 1 ) to give the title dianion, 2 ‐2Li, is a facile reaction. An analysis of the charge distribution by means of the 13 C NMR chemical shifts further confirms conclusions reached on the basis of MNDO calculations: Y‐conjugated trimethylenemethane dianions are more stable than cyclobutadienyl dianions. Hückel theory does not give reliable predictions for small doubly charged systems which are dominated by electrostatic repulsions.