Efficient Diels–Alder Reaction of 1,2-Benzoquinones with Arynes and Its Utility in One-Pot Reactions

A new protocol for the efficient Diels–Alder reaction of 1,2-benzoquinones with arynes is reported. The aryne generated by the fluoride-induced 1,2-elimination of 2-(trimethylsilyl)aryl triflates undergoes a facile Diels–Alder reaction with 1,2-benzoquinones, affording the dioxobenzobicyclooctadienes in moderate to excellent yields. In addition, this methodology has been applied to the one-pot synthesis of benzoquinoxalinobarrelene and naphthalene derivatives

Employing Arynes in Transition-Metal-Free Monoarylation of Aromatic Tertiary Amines

The highly monoselective N-arylation of aromatic tertiary amines using a transition-metal-free approach using arynes has been developed. The reaction afforded functionalized diaryl amines in moderate to excellent yield. High levels of functional group compatibility especially with halogen containing substrates, dyes and donor–acceptor systems, and high yields of products are the notable features of the present reaction

Practical Synthesis of Phthalimides and Benzamides by a Multicomponent Reaction Involving Arynes, Isocyanides, and CO₂/H₂O

Transition-metal-free multicomponent reactions involving arynes and isocyanides with either CO₂ or H₂O have been reported. With CO₂ as the third component, the reactions resulted in the formation of <i>N</i>-substituted phthalimides. The utility of water as the third component furnished benzamide derivatives in moderate to good yields. These reactions took place under mild conditions with broad scope

Stereoselective Alkyne Hydrohalogenation by Trapping of Transfer Hydrogenation Intermediates

A catalytically generated vinylcopper complex, the reactive intermediate of a copper­(I)-catalyzed alkyne transfer hydrogenation, can be trapped by commercially available halogen electrophiles. In this manner, internal alkynes can stereoselectively be hydrohalogenated to the corresponding vinyl chlorides, bromides, and iodides

Stereoselective Alkyne Hydrohalogenation by Trapping of Transfer Hydrogenation Intermediates

A catalytically generated vinylcopper complex, the reactive intermediate of a copper­(I)-catalyzed alkyne transfer hydrogenation, can be trapped by commercially available halogen electrophiles. In this manner, internal alkynes can stereoselectively be hydrohalogenated to the corresponding vinyl chlorides, bromides, and iodides

Metal-Free, Brønsted Acid-Catalyzed Formal [3+2] Annulation of Quinone Monoacetals with 2‑Naphthols

An operationally simple and metal-free cross-coupling of quinone monoacetals (QMAs) with 2-naphthols catalyzed by triflic acid is reported. This formal [3+2] annulation allowed the synthesis of diverse naphtho­[2,1-<i>b</i>]­benzofuran derivatives in moderate to good yields. Preliminary mechanistic studies reveal the initial nucleophilic substitution of QMAs with 2-naphthols in preference to the mixed acetal formation and subsequent [3,3] sigmatropic rearrangement

Asymmetric N‑Heterocyclic Carbene (NHC)-Catalyzed Annulation of Modified Enals with Enolizable Aldehydes

N-Heterocyclic carbene (NHC)-catalyzed highly enantioselective lactonization of modified enals with enolizable aldehydes, proceeding via the α,β-unsaturated acylazolium intermediates, is reported. The reaction results in the asymmetric synthesis of synthetically important 4,5-disubstituted dihydropyranones

The Aryne [2,3] Stevens Rearrangement

Arynes are employed in the transition-metal-free and mild [2,3] Stevens rearrangement of tertiary allylic amines for the synthesis of functionalized homoallylic amines in moderate to good yield with a broad substrate scope. The key nitrogen ylide intermediate was generated by the <i>N</i>-arylation of allyl amines using arynes. Moreover, the reaction of chiral allyl amines with arynes resulted in the enantiospecific synthesis of homoallylic amines. In addition, preliminary studies on the [1,2] Stevens rearrangement is also presented