Résumé
Scheschkewitz and Alabugin et al. suggest that photolysis under confinement in a crystalline matrix of 4,6-dimethyl-alpha-pyrone does not yield the crystal structure of 1,3-dimethylcyclobutadiene (Me2CBD) as we reported, but rather that of a 4,6-dimethyl-beta-lactone intermediate. We provide arguments that the square-planar Me2CBDS/CO2 complex and the rectangular-bent Me2CBDR molecule are stabilized under confinement by the guanidinium-sulfonate-calixarene host matrix used in our study.