NHC‐Catalyzed Cascade Reactions for the Construction of Fused Cycles via LUMO Activation of α,β‐Unsaturated Carbonyls

Abstract

The facile syntheses of multicyclic molecules through multi-step cascade reactions with N-Heterocyclic carbene (NHC)-catalyzed LUMO activation strategies are summarized. The reaction mechanisms involved in these cascade catalytic transformations are also provided and discussed. The review article is arranged according to the reaction starting materials that are used for the NHC-catalytic activation processes.

NHC-Catalyzed Reaction of Aldehydes for C(sp2)–O Bond Formation

“…In recent years, the use of chiral NHCs has attracted substantial attention for the enantioselective synthesis of various molecules with structural diversity and complexity [10][11][12][13][14][15][16][17][18][19][20][21][22]. Furthermore, new methods and strategies for NHC catalysis are emerging continuously, leading to the remarkable progress in the cooperative catalysis with Lewis acid, Brønsted acid, hydrogen-bonding organocatalyst, and transition-metal catalyst [23][24][25][26][27].…”