Microwave-accelerated spiro-cyclizations of o-halobenzyl cyclohexenyl ethers by palladium(0) catalysis

A number of new spiro[cyclohexane-1,1'-isobenzofuran]-based compounds was synthesized by palladium(0)-catalyzed 5-exo cyclization of a series of cyclohexenyl o-halobenzyl ethers. Controlled microwave heating was found to promote both product yield and reaction rate without compromising the selectivity. Heck cyclization of aryl iodide 6, 2-(2-iodobenzyloxy)cyclohex-2-enyl acetate, proceeded selectively without involvement of the allylic acetate functionality.