Acceleration of the Diels-Alder Reaction between 9-Functionalized Anthracenes and C60/C70 in the Cavity of a Water Soluble Subphthalocyanine Cage

Herein we report on the acceleration of the Diels-Alder reaction between a series of 9-functionalized anthracenes and C-60/C-70 encapsulated in a water-soluble metallo-organic Pd(II)-subphthalocyanine cage (SubPc-cage), which performs as a catalytic molecular reactor that provides a beneficial hydrophobic environment. Negatively and positively charged anthracenes do not react either with C-60 or C-70, due to a favored solvation in water medium and/or to detrimental interactions with positively-charged Pd(II) corners of SubPc-cage. Experiments with C-60 and C-70 rendered parallel results, although C-70 proved more reactive, leading to anthracene cycloadducts by reaction in the alpha bonds. All the results have been rationalized by theoretical calculations at the GFN2-xTB level.