Esters propargylic-carbon monoxide reactions

REPPE PROCESS. Any of several processes involving reaction of acetylene (1) with formaldehyde to produce 2-butync-l,4-diol which can be converted to butadiene (2) with formaldehyde under different conditions to produce propargyl alcohol and, form this, allyl alcohol (3) with hydrogen cyanide to yield acrylonitrile (4) with alcohols to give vinyl ethers (5) with amines or phenols to give vinyl derivatives (6) with carbon monoxide and alcohols to give esters of acrylic acid (7) by polymerization to produce cyclooctatetraene and (8) with phenols to make resins. The use of catalysis, pressures up to 30 atm, and special techniques to avoid or contain explosions are important factors in these processes. 

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. 

Propargylic mesylates are converted to the transposed 2,3-alkadienoic esters and amides by (PhjP) Pd and CO in the presence of alcohols and arylamines, respectively. These allenoic acid derivatives are precursors of butenolides. In a synthesis of kallolide-B, this reaction is the critical step (PhjP) Pd is generated in situ from (dba)3Pd2 and PhjP in the presence of carbon monoxide. ... 

Two different types of tandem reactions for the synthesis of highly functionalized cyclohexenones cyclopropyl-substituted propargyl esters initiated rhodium-catalysed Saucy-Marbet 1,3-acyloxy migration have been reported (Scheme 152). The resulting cyclopropyl-substituted allenes derived from acyloxy migration followed by 5 -f 1-cycloaddition with carbon monoxide. ... 

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