Acetylenic ethers reactions with metal carbonyls

Three important processes have evolved from Reppe s work. Vinylation, the formation of vinyl derivatives by reaction of such compounds as acids, glycols, and alcohols with acetylene, produces the important vinyl esters and vinyl ethers. Ethinylation is defined as the reaction of acetylene with the carbon atom of a reactant without loss of the triple bond. A major application of the ethinylation reaction is to aldehydes and ketones to give alkynols and alkyndiols—e.g., the reaction of acetylene with formaldehyde to give propargyl alcohol and butyn-2-diol-l,4. Carboxylation (also referred to as carbonylation), the reaction of acetylene with carbon monoxide in the presence of metal carbonyls, has been applied to the production of acrylic acid, acrylates, and hydroquinone. 

Transition-metal-promoted carbonylation reactions continue to provide interesting new routes to a-methylene lactones. The /runs -vinyl bromide (156) reacts with Ni(CO)4 to give the c -fused lactone (157) in 95% yield. By contrast, the reaction of the frans -acetylenic alcohol (158) with carbon monoxide and PdCl2 leads to the frans-fused lactone corresponding to (157). The ether (159) has been oxidized with CrOs-pyridine to the corresponding lactone, which was obtained as a mixture of isomers in modest yield. ... 

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