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[Display omitted] • The synthetic method of 3,4-dihydro-[1,3]oxazin-2-ones mediated by BF 3 ·Et 2 O. • This method uses BF 3 ·Et 2 O as Lewis acid. • The yield was moderate to good. An efficient one-pot approach to access functionalized 3,4-dihydro-[1,3]oxazin-2-one skeletons has been developed through BF 3 ·Et 2 O-mediated addition-cyclization of ynamides and N- Boc phenylsulfones. The metal-free catalytic method exhibits good functional group compatibility. This study provides a practical new method for the synthesis of oxazinone skeletons. [ABSTRACT FROM AUTHOR]

[Display omitted] An In(OTf) 3 -catalyzed oxygenative bifunctionalization reaction has been developed for the facile synthesis of various α-functionalized ketones. A wide range of aryl sulfoxides and electron-rich arylalkynes prove to be suitable substrates for this transformation. The potential of our method was then extended to the synthesis of 8-substituted quinolines from ynamides and quinoline- N -oxides. [ABSTRACT FROM AUTHOR]

[Display omitted] A divergent transformation of ynamides with anthranils has been reported, which leads to the synthesis of various 7-acylindoles and 2-aminoquinolines in moderate to excellent yields. Indium(III) triflate is used as a cheap and readily available catalyst and the method exhibits high functional group tolerance. [ABSTRACT FROM AUTHOR]

[Display omitted] A simple HNTf 2 /DMSO system has been developed for the intermolecular oxgenative bifunctionalization of ynamides to produce various α -functionalized amides, where DMSO functions both as the oxygen donor and the solvent. Scope study shows that electron-rich ynamides and nucleophiles such as alcohols, thiols and electron-rich arenes are suitable reaction partners in this transformation. [ABSTRACT FROM AUTHOR]

Ynamides are versatile 3-atoms building blocks for organic synthesis as they participate in a variety of ionic, radical and pericyclic processes. Converting ynamides into 5-atom building blocks, such as the yet unreported N -vinyl ynamides, would open new avenues in this fascinating chemistry. We describe herein our efforts towards such goal and demonstrate that the cross-coupling between N -vinyl carbamates and bromo-alkynes using copper(I) thiophene carboxylate, 1,10-phenanthroline and tBuOK in DMSO is a reactive system with an improved profile compared to the classical ynamides syntheses. The advantages and limitations of this copper-mediated reaction are discussed. [ABSTRACT FROM AUTHOR]

The trifluoroacetic acid (TFA) mediated hydration of ynamides was developed, which is an efficient approach for the synthesis of N -monosubstituted amides. This convenient method is effective with a wide range of substrates under room temperature condition, and the products are obtained in high to excellent yields through an easy work-up process. [ABSTRACT FROM AUTHOR]

The synthesis of multi-ynamides according to the copper-catalyzed Evano’s and Hsung’s methods is described. In these new compounds, the ynamide functions are conjugated to each other with a phenyl, a biphenyl, a thienyl, or a triphenylamine spacer. [ABSTRACT FROM AUTHOR]

An intramolecular [2+2] cycloaddition using N -sulfonyl substituted ynamides tethered to an enone motif is described here. This thermally driven [2+2] cycloaddition manifold can be catalyzed effectively using AgNTf 2 , and represents the first examples of an intramolecular Ficini reaction. [ABSTRACT FROM AUTHOR]

Ynamides consist of a polarized triple bond that is directly attached to a nitrogen atom carrying a sulfonyl, an alkoxycarbonyl, an acyl, or another electron withdrawing group. The triple bond polarization renders ynamides broadly useful building blocks with synthetic opportunities that go far beyond traditional alkyne chemistry. The versatile reactivity of ynamides in cycloadditions, cycloisomerizations, regioselective additions with various nucleophiles or electrophiles, ring-closing metathesis, and many other reactions has been investigated in detail during the past decades. A common feature of these methods is that the triple bond is consumed and either cleaved or transformed to a new functionality. The wealth of reports on these ynamide reactions is in stark contrast to the dearth of carbon–carbon bond formations that leave the triple bond of terminal ynamides intact. The recent introduction of effective synthetic methods for the preparation of terminal ynamides has set the stage to fully explore the synthetic potential of this intriguing class of compounds. This digest Letter summarizes the most effective routes to terminal ynamides and the current state of selective nucleophilic addition, substitution, and coupling reactions, including the first examples of asymmetric synthesis. [ABSTRACT FROM AUTHOR]

Abstract: A convenient synthesis of 1-haloethenamides has been achieved by utilizing halotrimethylsilane (TMSX, X=Cl, Br, I) and water. Halotrimethylsilane in 1M CH2Cl2 solution functions as a halogen source of the in situ generated HX, and the HX added to the terminal triple bonds of ynamides in Markovnikov fashion. [Copyright &y& Elsevier]

Abstract: A facile approach to 1-(1-halovinyl)-1H-indoles from readily accessible 1-ethynyl-1H-indoles with in situ generated HX is described. The simple protocol enables a regio- and stereoselective hydrohalogenation to the triple bonds in gram-scale, and provides a general entry for novel N-alkenylindole derivatives. [Copyright &y& Elsevier]

Abstract: Ynamides were prepared through an efficient copper-catalyzed coupling reaction. In the presence of copper iodide, 1,10-phenanthroline, and Cs2CO3, the coupling reaction of 1,2-dibromo-1-styrenes with sulfonamides proceeded smoothly and generated the corresponding products with excellent isolated yields. [Copyright &y& Elsevier]

Abstract: A straightforward formation of six- and eight-membered rings via the radical cyclization of specifically designed ynamides is reported. This strategy provides a protoberberine analog in only three steps by a radical cyclization cascade. [Copyright &y& Elsevier]

Abstract: The first synthesis of 2-iodoynamides is described as well as the first [2+2] cycloadditions of ketene with iodo alkynes. [Copyright &y& Elsevier]

Abstract: Using ynamides as one of the reacting components, the Cu-catalyzed three-component reaction of sulfonyl or phosphoryl azides and amines affords α-amino amidines in high yields under mild conditions. Synthetic utility of the produced compounds was demonstrated in the diastereoselective alkylation of α-amino amidines bearing a chiral oxazolidinone moiety. It was also shown that α-amino imidates could be readily prepared by employing alcohols instead of amines. [Copyright &y& Elsevier]

Abstract: A highly regio- and stereoselective Brønsted acid-catalyzed coupling of ynamides and indoles is described. This process is the equivalent of hydroarylation of ynamides and leads to the efficient syntheses of vinylindoles. Diels–Alder reaction between the vinylindoles and DMAD afforded carbazole derivatives in good yields. [Copyright &y& Elsevier]

A highly regio- and stereoselective trans -hydrofluorination of N -sulfonyl ynamides has been realized with AgF as the fluorination reagent, affording ( Z )-α-fluoroenamides in good to excellent yields. The reaction proceeds under mild reaction conditions and shows good functional group compatibility. [ABSTRACT FROM AUTHOR]

[Display omitted] • A one-pot method to substituted 6-amino-3,4-dihydro-1,3-oxazin-2-ones skeleton. • Wide range of applicable substrates, suitable for benoimides and linear imides. • Efficient method and easy access to substrate. A one-pot approach to access functionalized 1,3-oxazin-2-one skeleton has been developed through successive reduction and subsequent [4 + 2] cyclization process of N -Boc lactams with ynamides by TMSOTf. As a result, a number of five to seven membered ring fused bicyclic [1,2-c] [1,3] oxazin-1-ones 12a-m and tricyclic derivatives 13a-f were obtained in moderate to excellent yields with excellent regioselectivities. Moreover, linear N -Boc amides 9a-e were also amenable to this transformation, and the desired 3,4-dihydro-1,3-oxazin-2-ones 14a-m were readily achieved in moderate yields with excellent regioselectivities. [ABSTRACT FROM AUTHOR]

• Dihydro-[1,3]oxazino[4,3-a] isoindole and tetrahydroisoquinoline skeletons. • Addition-cyclization of ynamides with N -acyliminium ions. • Cu(OTf) 2 catalyzed this transformation effectively. An efficient approach to access functionalized dihydro-[1,3]oxazino[4,3-a] isoindole and tetrahydroisoquinoline skeletons has been developed through the addition-cyclization process of ynamides 8 with N -acyliminium ions generated from N,O -acetals 6,7. The reactions were conducted under the catalysis of Cu(OTf) 2 , and a number of functionalized dihydro-[1,3]oxazino[4,3-a] isoindoles 9a-9y and tetrahydroisoquinolines 10a-10g, 11a-11p were generated in 48–98% yields. When chiral ynamides 8n-8u were used, optically pure products 11a-11p could be obtained with good to excellent yields and diastereoselectivities. [ABSTRACT FROM AUTHOR]

Abstract: A facile approach to (E)-α-haloenamide moieties from ynamides using bromo- or iodotrimethylsilane is described. The simple protocol enables a regio- and stereospecific hydrohalogenation of the triple bond in gram-scale and provides a general entry for synthesis of novel enamide analogues. [Copyright &y& Elsevier]

Abstract: The Ireland–Claisen rearrangement of propargyl ynamido ester substrates is reported. The expected allenamide carboxylic acid products from [3,3]-sigmatropic rearrangement are not isolated, with 2-amidodienes alternatively formed in good yield with high levels of stereocontrol after decarboxylation. [Copyright &y& Elsevier]

• Pd-catalyzed hydroarylations of ynamides in water with the water-soluble TPPTS ligand. • Regio- and stereoselectivity in favor of the (Z)-α,β-disubstituted enamides. • Β, β'- or α,β-disubstituted enamides in the presence of PCy 3 or P(o-Tol) 3 ligands. Pd-catalyzed hydroarylation reactions of ynamides were studied in pure water in the presence of the water-soluble industrial TPPTS ligand in comparison with the use of PCy 3 or P(o -Tol) 3. Pd(OAc) 2 /TPPTS (3,3′,3″-phosphanetriyltris(benzenesulfonic acid) trisodium salt) system exhibited high activity for the conversion of various aryl- and alkyl-ynamides in the presence of arylboronic acids bearing either electron-donating and electron-withdrawing groups. The hydroarylation reactions allowed the formation of (Z)-α,β-disubstituted enamides as major compounds in the case of arylynamides and as unique isomer in the case of alkylynamides. The reaction conditions were optimized and the presence of a base was necessary for the efficient preparation of enamides at room temperature. Conversely, α,β-disubstituted or β,β′-disubstituted enamides were isolated as major single stereoisomers and at room temperature in water in the absence of any additive by using PCy 3 or P(o -Tol) 3 , respectively. The best activity was observed for oxazolidin-2-one, whereas other a tosylynamide was non-reactive. [ABSTRACT FROM AUTHOR]