An unprecedented N-heterocyclic carbene and magnesium cocatalyzed three-component acylcyanoalkylation of alkenes with cycloketone oxime esters and aldehydes is presented. This method displayed good scope generality, providing a transition-metal- and photoredox-free pathway to access various multifunctionalized aliphatic keto nitrile structures under mild reaction conditions. Moreover, this strategy is supposed to follow a radical relay mechanism via a single electron transfer event of a Mg/matched Breslow intermediate/oxime ester electron-donating acceptor (EDA) complex.

Alkynyl acids are first utilized as alkynyl acylazolium precursors through an in situ activation strategy for the efficient construction of carbon‐sulfur bond in a formal [3+3] annulation. This protocol offers a direct and rapid pathway for the synthesis of imidazo[2,1‐b][1,3]thiazinone skeleton, a useful heterocyclic class frequently found in many bioactive compounds. This reaction also has the advantages of scalability, readily available materials, and simple manipulation in open air.magnified image

The structurally interesting pyrano[3,2-b]indol-2-ones were synthesized by an N-heterocyclic carbene-catalyzed formal [3 + 3] annulation of alkynoic acid esters.

An N-heterocyclic carbene (NHC)-catalyzed formal [4 + 2] annulation of 2-aryl-3H-indol-3-ones with α,β-unsaturated carboxylic acids bearing γ-H was developed via an in situ activation strategy. The reaction involves the γ-addition of vinyl enolates to the unique cyclic ketimines to afford chiral tricyclic indolin-3-ones with a quaternary carbon center at 2-position. This protocol provides a rapid and enantioselective pathway to access a novel class of structurally important C2-quaternary indolin-3-ones that might be useful for drug discovery.

An N-heterocyclic carbene (NHC)-catalyzed three-component tandem β-sulfonylation/esterification of α-bromoenals was developed.