Isomerisation, alkylation and hydroxyalkylation of cumulenyl ethers

Abstract

Abstract In dimethyl sulfoxide 1,2,3‐trienyl ethers RR′CCCCHOCH 3 (with R and R′ = alkyl or RR′C = cyclohexyl) are isomerised by potassium tert‐ butoxide, first to 1,2,4‐ and then to 1,3,5‐trienyl ethers. In the case of RR′C = cyclohexyl, thus with magnified image elimination of methanol takes place and further isomerisation finally leads to aromatisation to 1‐propenylbenzene. Acid hydrolysis of CH 2 = C(CH 3 )CHC = CHOCH 3 in dimethyl sulfoxide affords the aldehyde CH 2 C(CH 3 )CHCHCHO. The 1,2,3‐ and 1,2,4‐trienyl ethers have been metallated in the 1‐position by lithium amide and butyllithium, and subsequently alkylated or hydroxy‐alkylated. Recently 1,2,3‐trienyl ethers RR′CCCCHOCH 3 have become available 1 . The present paper describes some reactions with these compounds.