Improved procedure for functionalized 3,3-dimethoxycyclobutenes: Useful intermediates in organic synthesis

Article abstract of DOI:10.1055/s-1994-25424

The [2 + 2] cycloaddition of the 1,1-dimethoxyalkenes 1 and the electron- poor alkynes 2 in dry chloroform affords the functionalized 3,3- dimethoxycyclobutenes 3 in good to excellent yields (40-100%). The latter by electrocyclic ring opening give the dienes 4, starting materials to multifunctional compounds such as the esters 5 and the cyclohexenes 6.