ISSN:
0009-2940
Keywords:
Ruthenium compounds
;
Osmium compounds
;
Alkynes, activated
;
Cyclotrimerization
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Depending on the substituents, the reaction of the activated alkynes ZC≡CZ (2a-g) [Z = CO2R: R = Me (a), Et (b); Z = R1: R1 = CF3 (c), CH2Cl (d), CH2Br (e); Z = CH2OC(O)R2: R2 = Me (f), CCl3 (g)] with the labile ruthenium complex (η2-C2H4)Ru(CO)4 (1) results in the formation of three different types of heterocycles. While the reactions of the dialkyl acet-ylenedicarboxylates 2a, b lead to the dimeric tricarbonylru-thenacyclopentadienes 3a, b, being catalytically active in the cyclotrimerization of alkynes like 2a, b, the application of the 1,4-halogeno-2-butynes 2c-e yields the bicyclic heterocycles 4c-e. The esters of 2-butyne-1,4-diol 2f, g are converted into the tetracarbonylruthenacyclopentadienes 5f, g. Investigation of the primary attack of the alkynes 2a-g at complex 1 leads to the conclusion, that an ionic mechanism is preferred in the ruthenium-catalyzed cyclotrimerization of electron-poor alkynes. If, instead of 1, (η2-C2H4)Os(CO)4 (6) is allowed to react with the acetylenes 2a, b the osmium complexes (η4-C6Z6)Os(CO)3 (7a, b) are isolated. In the presence of CO at 2 bar 7a, b release the benzene derivatives C6Z6 (8a, b) with the formation of Os3(CO)12.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19941270803
