Studies of the reactions of some benzenalkenyl ethers with benzenselenenylhalides

Intramolecular cyclization of some benzenalkenyl ethers with benzenseleneny l halides (PhSeX, X=Cl and Br) at different temperatures (-78 degrees C, 0 degrees C and room temperature) has been investigated. It has been found th at Delta(4)-alkenyl benzyl ethers afford cyclic phenylselenoethers of the t etrahydrofuran and tetrahydropyran type, the ratio of which depends upon th e number and position of alkyl substituents at the double bond and at the c arbinol carbon atom. Delta(5)-Alkenyl benzyl ethers give only six-membered ether rings. The yield of cyclic phenylselenoether products decreases with an increase of the reaction temperature. PhSeCl is more efficient than PhSe Br for the cyclization reaction.