Organocatalytic transformations of alkynals, alkynones, propriolates, and related electron-deficient alkynes

Organocatalytic Reactions Enabled by N-Heterocyclic Carbenes

“…Notably, NHC-bound acylazolium and azolium enolate intermediates have attracted considerable attention over the last decade. 183 As in the case of NHC catalyzed umpolung reactions, the origins of α,β-unsaturated acylazoliums is biomimetic. In a set of cleverly designed experiments, Townsend and co-workers showed a thiamine diphosphate (ThDP, vitamin B 1 )-derived α,β-unsaturated acylazolium ion 123 is an intermediate in the biosynthesis of clavulanic acid ( 122 ), a potent β-lactamase inhibitor (Scheme 118).…”

Metal–Organic Frameworks Invert Molecular Reactivity: Lewis Acidic Phosphonium Zwitterions Catalyze the Aldol-Tishchenko Reaction

“…Although their main application lies in the field of transition metal catalyzed reactions, 8 e.g., the hydroformylation of olefins 9 and the asymmetric synthesis of fine chemicals and bioactive compounds, 10 phosphorus compounds gain increasing interest in organocatalytic reactions. 11 Phosphines as organocatalysts facilitate the reaction with unsaturated carbon atoms to form phosphonium zwitterions. 11d Such species are reactive toward nucleophilic attack and catalyze a variety of C–C bond forming reactions like the Michael addition and the Morita–Baylis–Hillman (MBH) reaction.…”

Tandem Reactions of Ynones: via Conjugate Addition of Nitrogen‐, Carbon‐, Oxygen‐, Boron‐, Silicon‐, Phosphorus‐, and Sulfur‐Containing Nucleophiles

“…The Dong group reviewed the synthesis of ynones and applications in transition metal‐catalyzed reactions. In this decade, both metal‐catalyzed and organocatalytic transformations were reviewed already. In 2016, Rulev and co‐workers described the use of polyfluoroynones in the synthesis of nitrogen‐bearing heterocycles.…”