Gold(I)‐Catalyzed Synthesis of Six‐Membered P,O‐Heterocycles via Hydration/Intramolecular Cyclization Cascade Reaction

Abstract

Herein, we report the synthesis of sixmembered P,O-heterocycles from dialkynylphosphine oxides. By using gold(I) complexes, the chemoselectivity of the reaction was switched from literature-reported double hydration to a hydration/ intramolecular cyclization cascade. Control experiments indicated that the first alkyne hydration product is an intermediate of the reaction. In addition, a density functional theory (DFT) calculation allowed to rationalize the observed chemoselectivity.

Advancements in Gold‐Catalyzed Cascade Reactions to Access Carbocycles and Heterocycles: An Overview

“…Tertiary amine substituted 3-en-1-yne was treated with anilines in presence of 5 mol% gold-catalyst, 10 mol% CF 3 SO 3 H in Wang's group described the synthesis of six-membered P, O-heterocycle scaffold 115 from di-alkynyl phosphine oxides 116 (Scheme 45). [84] For this purpose, the optimal reaction conditions were 5 mol% IPrAuCl, 1,2-dichloroethane as a solvent, 80 °C for 16 h treatment. This gold(I)-catalyzed chemoselective approach followed two key steps: hydration and followed by an intermolecular cyclization cascade reaction.…”

Regiodivergent Hydration–Cyclization of Diynones under Gold Catalysis

“…15 Herein, we report the gold(I)- catalyzed pathway-switchable tandem hydration-oxacyclization to 4-pyranones and 3(2H)-furanones from skipped diynones. 16 We selected symmetric diynone 2a as a model substrate for attempting the proposed hydration−cyclization reaction. After having assayed a variety of Lewis acids, we found that only gold(I) complexes 17 possess significant activity for the planned sequence using dioxane as solvent.…”