Chemistry of acetylenic ethers 87: Preparation of cumulenyl ethers by 1,4‐elimination

Cumulenyl ethers of the type R′R″C  C  C  CHOCH3 (with R′ and R″ alkyl) have been prepared in good yields by treatment of bis‐ethers of the type (C2H5O)CH(CH3)OC(R′)(R″)CCCH2OCH3 with two equivalents of sodamide in liquid ammonia. From the bis‐ether (C2H5O)CH(CH3)OCH(CH3)CCCH2OCH3 a mixture of cis and trans CH3CCCH  CHOCH3 was obtained in good yield by the same procedure.