Potential applications of Zr-KIT-5: Hantzsch reaction, Meerwein-Ponndorf-Verley (MPV) reduction of 4-tert-butylcyclohexanone, and Prins reaction of citronellal

The acidity of Zr-incorporated large pore cubic mesoporous silicate, KIT-5, with Fm3m symmetry was explored as catalyst in the Hantzsch reaction for preparation of 1,4-dihydropyridine (DHP) derivatives, Meerwein-Ponndorf-Verley (MPV) reduction of 4-tert-butylcyclohexanone, and Prins reaction of citronellal. The catalyst showed similar to 82-94 % selectivity for formation of DHP derivatives based on substituted benzaldehydes. For the intramolecular cyclization of citronellal, the activity and isomer selectivity increased with Zr content. Both these reactions proceeded to nearly total conversion in relatively short reaction times of 3 h and 30 min, respectively. In sharp contrast, MPV reduction of 4-tert-butylcyclohexanone yielded 95 % conversion in 4 days, similar to those reported for Zr-TUD-1.