Allenes and Acetylenes. 28. On the Mechanism of Reduction of Propargylic Ethers and Acetates with Organocuprates

Article abstract of DOI:10.1021/jo00196a003

The amounts of substitution and reduction products from the reaction of two types of propargylic methyl ethers and acetates with organocuprates were determined.The methyl ethers give rise to more of the reduction products than the acetates.It is shown that "reduced" allenes are formed by hydrolysis of an organometallic intermediate whereas "reduced" acetyles are formed mainly by another mechanistic pathway.The mechanisms of these reduction reactions are discussed in terms of stabilized, transient Cu(III)-intermediates and concerted β-hydride transfer in the formation of the acetylene.