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Direct 13 C‐NMR Spectroscopic Observation of Cyclopropylidene Bromolithiocarbenoids
Author(s) -
Seebach Dieter,
Siegel Herbert,
Müllen Klaus,
Hiltbrunner Kurt
Publication year - 1979
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.197907841
Subject(s) - carbanion , chemistry , carbene , carbon 13 nmr , nuclear magnetic resonance spectroscopy , derivative (finance) , crystallography , stereochemistry , catalysis , organic chemistry , financial economics , economics
The nature of the cabenoid 1‐bromo‐1‐lithiocyclopropanes has been examined with 13 C‐labeled compounds at −100°C by 13 C‐NMR spectroscopy. The pronounced downfield shifts of the cabenoid C signsl suggest considerable weakening of the CBr bond (1) or even rehybridization (2) . Thus a LiBr‐complexed carbene appears more likely than a carbanion derivative.