94400-23-4Relevant articles and documents
The Preparation of Ethyl and Isopropyl Dienol Ethers and Dienol Pivalate Esters from Hagemann's Ester and its t-Butyl Analouge, and the Reactions of the Derived Ester Dienolates with Electrophiles
Baker, Murray V.,Ghitgas, Christine,Haynes, Richard K.,Hilliker, Audrey E.,Lynch, Gregory J.,et al.
, p. 2037 - 2058 (2007/10/02)
The preparation of ethyl 4-ethoxy-2-methylcyclohexa-1,3-diene-1-carboxylate, ethyl 4-isopropoxy-2-methylcyclohexa-1,3-diene-1-carboxylate, t-butyl 4-isopropoxy-2-methylcyclohexa-1,3-diene-1-carboxylate, ethyl 4-(t-butylcarbonyloxy)-2-methylcyclohexa-1,3-diene-1-carboxylate, and t-butyl 4-(t-butylcarbonyloxy)-2-methylcyclohexa-1,3-diene-1-carboxylate from Hagemann's ester and its t-butyl analogue in the presence of diethyl or diisopropyl sulfates and sodium hydride in dimethyl sulfoxide, or pivaloyl chloride and N,N,N',N'-tetramethylethylenediamine in tetrahydrofuran is described.The foregoing dienol ethers and esters are smoothly deprotonated by lithium diisopropylamide in tetrahydrofuran at -78 deg C to give corresponding ester dienolates, which react regiospecifically with a number of electrophiles, either α or γ to the alkoxycarbonyl group of the dienol ether or ester.A number of the products, which are generally obtained in good yields, have been hydrolysed to Hagemann's ester dirvatives substituted exclusively at C 1.
