Treatment of (CO)5W[C(OCH3)C(CH3CH2] (1) with C2H5(CH3)2CONa in THF at -78°C followed by HCl produced: (CO)5W[C(OCH3)CH(CH3)CH2OC(CH3)2C2H5] (3) (1%), C2H5(CH3)2CO(CO)5W[C(OCH3)C(CH3)CH2]CH2C(CH3)CH(OCH3) (5) (<1%), C2H5(CH3)2CO (CO)5W[C(OCH3)C(CH3)CH2]2H (6) (<1%), and the (μ-tris(carbene))trimetallic complex C2H5(CH3)2CO(CO)5W[C(OCH3)C(CH3)CH2]3CH2C(CH3)CH(OCH3) (9) (15%) as well as several, as yet, unidentified compounds. Complex 9 was characterized by analytical and spectroscopic methods; moreover, it was converted to the corresponding triester (10) upon PDC/DMSO oxidation. Upon standing at 0°C for long periods complex 1 was converted into a new (μ-bis(carbene))ditungsten complex (CO)5WC(OCH3)[CH(CH3)CH2CH2C(CH2)]C(OCH3)W(CO)5 (11) in low yield.
Bibliographical noteFunding Information:
We wish to thank the Bureau of General Research (Kansas State University) for support of this research. High resolution mass spectra were performed by the Midwest Center for Mass Spectroscopy, a National Science Foundation Regional Instrumentation Facility (Grant No. CHE 8211164).