SYNTHESIS AND DIELS-ALDER REACTIONS OF OXY-2-[(TERT-BUTYLDIMETHYLSILY)OXY]-1,3-BUTADIENES - APPLICATION TO THE SYNTHESIS OF TRIARYL ETHERS

A novel class of tetrahetero-substituted 1,3-dienes 1a-d having aryl e ther substituents at the 1,3-positions were synthesized by enol silyla tion of 4-substituted 1,3-diphenoxy-3-buten-2-ones-3a-c. The 1Z,3Z con figuration of 1b has been assigned by X-ray crystallography. The synth esis of triaryl ethers utilizing a Diels-Alder approach involved react ion of diene la with methyl acrylate to furnish a 3:1 mixture of endo- and exo-adducts. Conversion of the adducts to cyclohexenone 8 and aro matization with DDQ gave triaryl ether 9. Cycloaddition reactions of l a, Ib with some conjugated alkenes exhibited excellent regiospecificit y and endo stereoselectivity.