SYNTHESIS OF 5,6,7,8-TETRAHDROQUINOLINES BY THERMOLYSIS OF OXIME O-ALLYL ETHERS IN THE PRESENCE OF BORON-TRIFLUORIDE ETHERATE

Thermolysis of cyclohexanone oxime O-crotyl and O-cinnamyl ether in th e presence of BF3-etherate regioselectively gave 4-methyl- and 4-pheny l-5,6,7,8-tetrahydroquinoline, while the addition of organic bases suc h as triethylamine and pyridine inhibited the rearrangement. These fin dings suggested that the addition of the acid made [1,2] shift the pre dominant one of the two possible transformations, [1,2] and [2,3] shif t, of the O-allyl ethers.