ISSN:
0947-3440
Schlagwort(e):
Carbenes
;
Ylides
;
Thiazol-2-ylidene
;
Dimerizations
;
Carbene dimer
;
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The synthesis, characterization and X-ray crystallographic structure determination are described for a stable thiazol-2-ylidene 2. This thiazol-2-ylidene is the first example of a stable, crystalline carbene in which the singlet carbene center bears a sulfur substituent. The carbene 2 is the closest stable analog of the important thiamin (vitamin B1) carbene. Although the thiazol-2-ylidene 2 is sufficiently stable to isolate at room temperature in the absence of moisture and oxygen, it will dimerize to form a normal carbene-carbene dimer {2}2. With the isolation and structure determination of both 2 and {22}, this system is the first in which a stable carbene and its corresponding dimer have been isolated and characterized. Additionally reported is the “reduced” 2H-thiazoline 2 · H2 in which the former carbene center in 2 has been reduced to a methylene (CH2) group. Thiazol-2-ylidenes with smaller groups on nitrogen (e.g. mesityl or methyl) are too unstable to allow easy isolation. The dimer from 3,4,5-trimethylthiazol-2-ylidene possesses a very unusual geometry in which one of the former carbene centers is planar while the second is pyramidal.
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jlac.199719970213
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