ISSN:
0941-1216
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Tetrathiafulvalenes. XXVIII. Diastereoselective Formation of Unsymmetrically Substituted TetrathiafulvalenesAs a part of our work on chemistry of tetrathiafulvalenes, we make a contribution to elucidate the mechanism of forming tetrathiafulvalenes starting from 1,3-dithiole derivatives. We describe the synthesis of unsymmetrically substituted tetrathiafulvalenes (8a-i) starting with the 2H-1,3-dithiolium salt (7a-i)/tert. amine, 2-ethylthio-1,3-dithiolium salt (5a-i)/triphenylphosphine or 1,3-dithiole-2-thione (4a-i)/triethyl phosphite. If the 1,3-dithiole derivatives are substituted by bulky groups the isolation of the cis- and trans-isomers was possible due to differences in the solubility. In these cases (8c-i) the predominant formation of the cis-isomer is observed in the reaction of 2-ethylthio-1,3-dithiolium salts (5c-i) with triphenylphosphine or 1,3-dithiole-2-thiones (4c-i) with triethyl phosphite. This result is in agreement with the formation of an intermediate, analogously to the Wittig reaction. In the reaction of 2H-1,3-dithiolium salts (7a-i) with tertiary amines the relation of isolated cis- and trans-isomers is not 1:1 and depends on the bulkiness of the tertiary amine. These observations exclude in these three reactions a carbene mechanism for the dimerization of the 1,3-dithiole units to tetrathiafulvalenes.
Additional Material:
5 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prac.19963380199
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