ARBON MONOXIDE

At a one-to-one pressure ratio of ethylene tomajor product is succinate this is in contrast to the production of acrylic acid, where succinic add was not isolated. If the olefin is left out of the reaction mix, then oxalates are produced and this is a practical route to oxalates, particularly at carbon monoxide pressures above 500 psig. The formation of water is a severe problem for the stability and activity of the catalytic system, since in the presence of water there is a parallel reaction which produces considerable amounts of carbon dioxide. 

The hydrosilylation of unsaturated carbon-rhodium-catalyzed silylcarbocyclizations. In the presence of Rli4(CO)i2 and triethoxysilane, a rigid triyne backbone can undergo a silylcarbotricyclization cascade reaction to yield [5,6,5]-tricycles (eq 16). Similar to the results observed by Sieburth for the hydrosilylation of enamines, the alkoxysilane functionality provides significant rate enhancement in comparison to silylcarbocyclizations using alkyl- and arylsilane reagents. The incorporation of carbonyl functionality as terminal electrophiles into these cyclizations has also been successful. Rhodium-catalyzed carbonylative silylcarbocyclizations proceed in the presence of carbon monoxide (10 atm) to incorporate a carbonyl unit, usually as the aldehyde. Both of these tandem ad-dition/cyclization strategies produce functionalized carbocycles with simultaneous incorporation of sUyl functionality as aryl- and vinylsilanes. These alkenylsilanes can then be exploited for further synthetic manipulations as discussed above. "" ... 

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