Angularly fused triquinanes from linear substrates through trimethylenemethane diyl [2 + 3] cycloaddition reaction.

Angularly fused triquinanes were synthesized from linear dienes and phenyl(propynyl)iodonium salt through trimethylenemethane (TMM) diyl mediated [2 + 3] cycloaddition reaction. TMM diyl intermediates were obtained from alkylidene carbenes generated from reactions of alkynyliodonium salts with nucleophiles.