ISSN:
0009-2940
Keywords:
Organolithium compounds, α-oxygen-substituted
;
Reactions with nucleophiles
;
13C NMR of the carbenoid C atom
;
Calculations, IGLO
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
In addition to the earlier[1] demonstrated C-O bond elongation between the anionic carbon atom and oxygen in α-lithiated ethers which indicates a carbenoid character of these compounds we provide further evidence for this property in this publication. Thus, α-lithiated ethers RCH(Li)-OR' react as electrophiles with nucleophiles R' Li to give RCH(Li)-R' + LiOR', and the 13C-NMR signal of the carbenoid C atom is shifted downfield (compared to the 13C signal of the corresponding non-lithiated compound). Since the latter two observations are also made in the Li/Hal carbenoid series, α-lithiated ethers indeed are Li/oxygen carbenoids. Furthermore, for the first time we have calculated the 13C shifts of carbenoid C atoms in the Li/oxygen carbenoid series by means of the IGLO method: the calculated data agree nicely with the experimental ones. They even allow the preferred bridged structure in solution to be determined.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19931260819