Enantio- and Periselective Nitroalkene Diels-Alder Reactions Catalyzed by Helical-Chiral Hydrogen Bond Donor Catalysts

Abstract

Helical-chiral double hydrogen bond donor catalysts promote the nitroalkene Diels-Alder reaction in an enantio-and periselective manner. This represents the first asymmetric catalytic nitroalkene Diels-Alder reaction via LUMO-lowering catalysis. To gain an insight into this new process, the substrate scope of our catalyst was investigated by exploiting readily available 5-substituted pentamethylcyclopentadienes. The catalyst was found to tolerate dienes with different steric demands as well as dienes substituted with heteroatoms. The synthetic utility of 5-substituted pentamethylcyclopentadienes is rather limited, and thus we have developed a three-step route to 1,4,5,5-tetrasubstituted cyclopentadienes from commercially available ketones.

Recent progress in the field of cycloaddition reactions involving conjugated nitroalkenes

“…In 2012, Narcis et al 49 , submitted the periselective Diels-Alder reaction of nitroethylene with 5substituted pentamethylcyclopentadienes which has been realized by helical-chiral hydrogen bond donor catalysts -(M)-catalysts. Cycloadducts are obtained in this reactions with relatively high yields 38-84% (Table 20).…”