MOF-808 as a Highly Active Catalyst for the Diastereoselective Reduction of Substituted Cyclohexanones

Zr-containing MOF-808 is an excellent heterogeneous catalyst for the diastereoselective Meerwein-Ponndorf-Verley reduction of substituted cyclohexanones. The presence of substituents at the 2 or 3 position of the cyclohexanone ring strongly drives the reaction towards the formation of one of the two possible isomers. For 3-methyl cyclohexanone, the available space inside the MOF pores allows the formation of the bulkier transition state leading to the thermodynamically stable 3-cis-cyclohexanol. For 2-methyl cyclohexanone, the reaction rate is much slower and the final diastereoselectivity depends on the size of the alcohol used. Finally, reduction of 2-phenyl cyclohexanone is considerable faster over MOF-808 than for any other catalyst reported so far. The large size of the phenyl favors the selective formation (up to 94% selectivity) of the cis-alcohol, which goes through a less hindered transition state.

Automated summary

Zr-containing MOF-808 is an excellent heterogeneous catalyst for the diastereoselective Meerwein-Ponndorf-Verley reduction of substituted cyclohexanones. The presence of substituents at specific positions drives the reaction towards the formation of specific isomers, and the porous structure of the MOF allows for selectivity.