86177-65-3Relevant academic research and scientific papers
Alkyl-CO insertion reactions of (PMePh2)(CO)3Co η1-methyl, methoxymethyl, and carbomethoxymethyl complexes
Tso, Chung C.,Cutler, Alan R.
, p. 1834 - 1840 (2008/10/08)
The reactions of CO (1 atm) or excess PMePh2 with (PMePh2)(CO)3Co-R [R = CH3 (5), CH2OCH3 (8), CH2CO2CH2CH3 (12)] and with (PMePh2)2(CO)2Co-CH2OCH3 (10) are reported. The mono(phosphine) cobalt methyl (5) and methoxymethyl (8) compounds quickly add CO and give their stable acyl complexes (PMePh2)(CO)3Co-COR [R = CH3 (6), CH2OCH3 (9)]. Neither acyl dissociates CO or phosphine in solution. Reactions of 5 and 8 with PMePh2 afford the unstable bis (phosphine) acyl complexes (PMePh2)2-(CO)2Co-COR [R = CH3 (7), CH2OCH3 (11)]. These acyl complexes readily dissociate PMePh2 in solution and regenerate 5 and 8, respectively; upon treating with CO, 11 accordingly generates 9. Thus, carbonylating 10 affords first 11 and then 9. Carbethoxymethyl compound 12 is inert to CO under these conditions. The desired carbethoxyacetyl complex (PMePh2)(CO)3CoCOCH2CO2CH 2CH3 (13) interestingly is independently available by either metalating ethyl malonyl chloride or by treating (CO)4CoCH2CO2CH2CH3 with PMePh2. Once prepared, 13 deinserts CO and generates 12 (half-life in CH2Cl2 solution, 9 h). Therefore, if 13 did form in appreciable concentration from carbonylation attempts on 12 (typically 1-2-h duration), then it would have been detected. All organocobalt complexes were purified by column chromatography and were characterized by IR and 1H, 13C, and 31P NMR spectral procedures and in some cases by elemental analysis.
The role of acetyl complexes in the cobalt-catalyzed homologation of methanol
Martin, Jeffrey T.,Baird, Michael C.
, p. 1073 - 1078 (2008/10/08)
It is shown that stoichiometric hydrogenation of MeCOCo(CO)3PMePh2 in methanol yields a product distribution similar to that obtained during the homologation of methanol catalyzed by [Co(CO)3PMePh2]2. The result suggests that the acetyl compound is an intermediate during the catalytic reaction.
