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

Abstract

Scheme 12. Enamines:T BAF-catalyzed cyclization.Scheme 13. Intramolecular cyclization.Scheme14. Intramolecular cyclizations.Scheme15. CÀNa nd OÀNb ond cleavage. Scheme 16. Applications of RNH-Nu. Scheme 17. NH-sulfoximines and NH-sulfondiimines. Scheme18. Radical cyclizationf or the synthesis of indoles. Scheme 22. 2H-Azirines:[3 + +2] cycloadditions. Scheme 23. Visible light-induced cycloaddition for pyrrole synthesis. Scheme24. Cyclization and sulfonyl migration. Scheme 25. NR 2 -E strategy analysis. Scheme 57. Several arenes for annulations. Scheme 58. Conjugateaddition. Scheme 59. Asymmetric conjugate addition.Scheme60. Conjugatea ddition andcyclization.

Reagent-free intramolecular hydrofunctionalization: a regioselective 6-endo-dig cyclization of o-alkynoylphenols

“…6,10,[12][13][14] Besides, a few metal-free synthetic methods for acid-or base-catalyzed reactions have been studied, particularly for the intramolecular alkoxylation of o-alkynoylphenols (Scheme 1C). 8,[15][16][17][18][19] The alkoxylation might be achieved owing to the presence of both the reactive carbonyl and the polarized α,β-alkyne moieties (i.e., ynones). 18,20,21 However, these methods are not very appropriate in the context of green chemistry principles because they require expensive metal catalysts, harsh reaction conditions, and complex workup and purification.…”

Base‐Promoted Synthesis of Polysubstituted 4‐Aminoquinolines from Ynones and 2‐Aminobenzonitriles under Transition‐Metal‐Free Conditions

“…Based on the above observation and previous report, 24] we proposed a mechanistic pathway for the synthesis of polysubstituted 4-aminoquinolines as described in Scheme 4. The mechanism initially leads through the deprotonation of amine moiety of 2 which facilitates nucleophilic attack on ynone via aza-Micheal pathway to generate reactive species enolicallene A.…”

Recent Advances of Cinnamic Acids in Organic Synthesis

“…Especially, substituted alkenes could be efficiently obtained by an addition‐decarboxylation strategy. As both propiolic acids and ynones have similar structure with cinnamic acids, which contain electrophilic unsaturated bonds and electron‐withdrawing groups. Hence, our previous review can be used as a reference for the radical and Michael addition.…”

“…N ‐methyl‐formamide and N ‐methylacetamide were not suitable for this method. Interestingly, if nano CuO was used in reactions with NMP (or pyrrolidin‐2‐one), the alkene products would be obtained. In 2020, Fu and co‐workers presented a photocatalytic decarboxylative alkenylation.…”