ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The complexes of the type [ReH(CO)5-n(PMe3)n] (n = 4, 3) were reacted with aldehydes, CO2, and RC≡CCOOMe (R = H, Me) to establish a phosphine-substitutional effect on the reactivity of the Re-H bond. In the series 1-3, benzaldehyde showed conversion with only 3 to afford a (benzyloxy)carbonyltetrakis(trimethylphosphine)rhenium complex 4. Pyridine-2-carbaldehyde allowed reaction with all hydrides 1-3. With 1 and 2, the same dicarbonyl[(pyridin-2-yl)methoxy-O, N]bis(trimethylphosphine)rhenium 5b was formed with the intermediacy of a [(pyridin-2-yl)methoxy-O]-ligated species and extrusion of CO or PMe3, respectively. The analogous conversion of 3 afforded the carbonyl[(pyridin-2-yl)methoxy-O,N]tris(trimethylphosphine)rhenium (1) 7b. While 1 did not react with CO2, 2 and 3 yielded under relatively mild conditions the formato-ligated [Re(HCO2)(CO)(L)(PMe3)3] species (8 (L = CO) and 9 (L = PMe3)). Methyl propiolate and methyl butynoate were transformed, in the presence of 1, to [Re{C(CO2Me)=CHR}(CO)3(PMe3)2] systems (10a (R = H), and 10b(R = Me)), with prevailing α-metallation and trans-insertion stereochemistry. Similarly, HC≡CCO2Me afforded with 2 and 3, the α-metallation products [Re{C(CO2Me)=CH2}(CO)(L)(PMe3)3] 11 (L = CO) and 12(L = PMe3). The methyl butyonate insertion into 2 resulted in formation of a mixture of the (Z)- and (E)-isomers of [Re{C(CO2Me)=CHMe} (CO)2(PMe3)3] (13a,b). In the case of the conversion of 3 with MeC≡CCO2Me, a Re-H cis-addition product [Re{(E)-C(CO2Me)=CHMe}(CO)(PMe3)4] (14) was selectively obtained. Complex 11 was characterized by an X-ray crystal-structure analysis.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19940770813
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