REACTIONS OF TRIALKYLSILYL METAL CARBONYL COMPLEXES WITH ALDEHYDES AND KETONES.

摘要

The reactions of (CO)(,5)MnSiMe(,3) (1), (CO)(,4)Fe(SiMe(,3))(,2) (11), and(, )(CO)(,4)FeSiMe(,2)CH(,2)CH(,2)SiMe(,2) (14) with aldehydes and ketones have(' )been investigated as a means of developing new metal-carbon bondforming reactions.; Benzaldehyde and 1 react over 2 weeks at 5(DEGREES)C to give thesilyloxybenzyl complex (CO)(,5)MnCH(OSiMe(,3))(Ph) (2a) in 65%-90% yield, depending on conditions. 2a undergoes thermaldecomposition to Mn(,2)(CO)(,10) and the diastereomeric pinacolethers {lcub} CH(OSiMe(,3))(Ph){rcub}(,2) (3a,b). Reactions of 1 with p-methoxy-benzaldehyde and p-dimethylaminobenzaldehyde are much fasterbut yield organometallic products which are less stable towardsthermal decomposition.; 1 and butyraldehyde react to give (CO)(,5)MnH and the E and Z (3:2 ratio) isomers of butyraldehyde trimethylsilyl enol ether. The isolation of (CO)(,5)MnCOCH(n-C(,3)H(,7))(OSiMe(,3)) (10) when this reaction is carried out under 10 atm of CO provides good evidence for the formation of the alkyl complex (CO)(,5)MnCH(n-C(,3)H(,7))(OSiMe(,3)).; With ketones (acetone, cyclohexanone) 1 reacts to give (CO)(,5)MnH and trimethylsilyl enol ethers.; 11 reacts with 1 equivalent of benzaldehyde to give 3a,b andthe new iron dimer {lcub}(CO)(,4)FeSiMe(,3){rcub}(,2) (13). 13 reacts further with benzaldehyde to give 3a,b and a mixture of iron carbonyls. 11 reacts with 1 equivalent of cyclohexanone to give an trimethylsilly enol ether product.; 14 reacts with benzaldehyde to give the cyclic disiloxane(, )OSiMe(,2)CH(,2)CH(,2)SiMe(,2) (17) in 95% yield. The only other volatile(' )product identified from this reaction was trans-stilbene in ca.yield. 17 was also formed in reactions of 14 with p-methoxy-benzaldehyde, p-dimethylaminobenzaldehyde, butyraldehyde,and octanal. In the presence of triphenylphosphine 14 reactedwith the above aldehydes to give 17 and ylide complexes of theformula(' )(CO)(,4)Fe{lcub}CH(R)(PPh(,3)){rcub}.; Mechanisms for these reactions and their relevance to Fischer-Tropsch chemistry are discussed.