Cross-coupling Of Terminal Alkynes Research Articles

Stereospecific and Regioselective Synthesis of E-Allylic Alcohols through Reductive Cross Coupling of Terminal Alkynes.

We have developed a convergent method for the synthesis of allylic alcohols that involves a reductive coupling of terminal alkynes with α-chloro boronic esters. The new method affords allylic alcohols with excellent regioselectivity (anti-Markovnikov) and an E/Z ratio greater than 200:1. The reaction can be performed in the presence of a wide range of functional groups and has a substrate scope that complements the stoichiometric alkenylation of α-chloro boronic esters performed using alkenyl lithium and Grignard reagents. The transformation is stereospecific and allows for the robust and highly selective synthesis of chiral allylic alcohols. Our studies support a mechanism that involves hydrocupration of the alkyne and cross-coupling of the alkenyl copper intermediate with α-chloro boronic esters. Experimental evidence excludes a radical mechanism of the cross-coupling step and is consistent with the formation of a boron-ate intermediate and a 1,2-metalate shift.

Cu-Based ternary deep eutectic solvents for homo- and cross-coupling reactions of terminal alkynes

The Cu-DES-promoted Glaser-type homo- and cross-coupling of terminal alkynes under exogenous-ligand-free, base-free, and additive-free conditions is described.

C–P Cross-Coupling of Terminal Alkynes with H-Phosphonates by a Copper Photocatalyst

C–P Cross-Coupling of Terminal Alkynes with H-Phosphonates by a Copper Photocatalyst

Selective Manganese-Catalyzed Dimerization and Cross-Coupling of Terminal Alkynes.

Herein, efficient manganese-catalyzed dimerization of terminal alkynes to afford 1,3-enynes is described. This reaction is atom economic, implementing an inexpensive, earth-abundant nonprecious metal catalyst. The precatalyst is the bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)]. The catalytic process is initiated by migratory insertion of a CO ligand into the Mn–alkyl bond to yield an acyl intermediate that undergoes rapid C–H bond cleavage of alkyne, forming an active Mn(I) acetylide catalyst [Mn(dippe)(CO)2(C≡CPh)(η2-HC≡CPh)] together with liberated butanal. A range of aromatic and aliphatic terminal alkynes were efficiently and selectively converted into head-to-head Z-1,3-enynes and head-to-tail gem-1,3-enynes, respectively, in good to excellent yields. Moreover, cross-coupling of aromatic and aliphatic alkynes selectively yields head-to-tail gem-1,3-enynes. In all cases, the reactions were performed at 70 °C with a catalyst loading of 1–2 mol %. A mechanism based on density functional theory (DFT) calculations is presented.

Homo- and Cross-Coupling of Terminal Alkynes on a Copper/Carbon Nitride Catalyst

Homo- and Cross-Coupling of Terminal Alkynes on a Copper/Carbon Nitride Catalyst

Recyclable Cu/C3N4 composite catalysed homo- and cross-coupling of terminal alkynes under mild conditions

A facile, practical and recyclable Cu–N–C composite catalyst with good catalytic activity for both homo- & cross-coupling of terminal alkynes.

A novel Zinc-catalyzed Cadiot-Chodkiewicz cross-coupling reaction of terminal alkynes with 1-bromoalkynes in ethanol solvent

A novel Et2Zn/L-proline catalyzed synthesis of symmetrical as well as unsymmetrical buta-1,3-diynes by the cross-coupling of terminal alkynes with 1-bromo alkynes in ethanol solvent was developed in good yields under simple and mild reaction conditions. The use of relatively non toxic and ecofriendly nature of Zn, inexpensive amino acid ligand L-proline and environmentally benign solvent EtOH make this protocol a better alternative for the synthesis of 1,3-diynes. The scope and limitations of this protocol were investigated.

Gold-Catalyzed Cadiot-Chodkiewicz-type Cross-Coupling of Terminal Alkynes with Alkynyl Hypervalent Iodine Reagents: Highly Selective Synthesis of Unsymmetrical 1,3-Diynes.

A new and efficient method for the synthesis of unsymmetrical 1,3-butadiynes by gold-catalyzed C(sp)-C(sp) cross-coupling of terminal alkynes with alkynyl hypervalent iodine(III) reagents has been developed. The reaction features high selectivity and efficiency, mild reaction conditions, wide substrate scope, and functional-group compatibility, and is a highly attractive complement to existing methods. Mechanistic studies reveal that formation of a phenanthrolinyl-ligated gold(I) complex is crucial for the efficiency and selectivity of the target transformation.

A copper-free, cross-coupling of terminal alkynes with hetaryl halides

Substituted ethynyl heterocycles and heteroarylbutenynes are synthesized efficiently in good yields via a copper-free, cross-coupling reaction.

Cross-Coupling of Terminal Alkynes with Hydrosilanes Using Au/OMS-2

Key words alkynes - silanes - cross-dehydrogenative coupling - gold - molecular sieves

Enaminone ligand-assisted homo- and cross-coupling of terminal alkynes under mild conditions

Abstract Copper-catalyzed oxidative coupling reactions of terminal alkynes have been performed at room temperature by using enaminone as effective ligand. Both symmetrical and unsymmetrical 1,3-diynes bearing various functional groups have been synthesized in moderate to excellent yields via homo- and cross-coupling reactions.

Nanosized Pd(0)-arabinogalactan composites as catalysts in the Sonogashira reaction

Zero-valent palladium nanoparticles stabilized by arabinogalactan polysaccharide matrix were successfully used for the first time as phosphine-free catalyst in the cross-coupling of terminal alkynes with aryl and hetaryl halides.

Copper(I) Iodide Catalyzed Cross-Coupling Reaction of Terminal Alkynes with 1-Bromoalkynes: A Simple Synthesis of Unsymmetrical Buta-1,3-diynes

A simple synthesis of unsymmetrical buta-1,3-diynes by cross-coupling of terminal alkynes with 1-bromoalkynes in the presence of copper(I) iodide and tris(o-tolyl)phosphine was developed that gives good yields under simple and mild reaction conditions. The scope and limitations of the cross-coupling reaction were investigated.

ChemInform Abstract: Palladium-Catalyzed Cross-Coupling of Terminal Alkynes with 4-Trifloyloxazole: Studies Toward the Construction of the C26-C31 Subunit of Phorboxazole A.

A strategy has been developed that successfully takes advantage of transition-metal-catalyzed coupling reactions for the synthesis of highly functionalized oxazoles. Trifloyloxazoles have been used...

Half-Sandwich Rare Earth Metal Complexes as Novel Catalysts for Olefin Polymerization and Other Chemical Transformations

Abstract This article describes our recent studies on the synthesis and chemistry of mono(cyclopentadienyl)-ligated rare earth metal alkyl and hydride complexes. The half-sandwich mono- and dialkyl rare earth metal complexes are prepared either by alkane elimination reactions between trialkyl rare earth complexes and the neutral cyclopentadiene derivatives or by metathetical reactions of rare earth trichlorides with the alkali metal salts of the corresponding ligands. The reaction of the dialkyl complexes with an equivalent of a borate compound such as [Ph3C][B(C6F5)4] or [PhNMe2H][B(C6F5)4] generates easily the corresponding cationic monoalkyl species, which serve as excellent catalysts for the polymerization and copolymerization of a variety of olefins to yield a new family of polymer materials that show novel properties but are difficult to prepare by other catalysts. The half-sandwich monoalkyl rare earth complexes bearing the silylene-linked cyclopentadienyl–arylamido ligands act as excellent catalysts for the catalytic dimerization of terminal alkynes, cross coupling of terminal alkynes with isocyanides, and the catalytic addition of terminal alkyne C–H, amine N–H, and phosphine P–H bonds to carbodiimides. The hydrogenolysis of the dialkyl rare earth complexes with H2 affords a new class of polynuclear rare earth metal polyhydride complexes, which show unique features in both structure and reactivity.

Sonogashira Cross‐Coupling of Arenediazonium Salts

Star-crossed lovers: The domino iododediazoniation/Sonogashira cross-coupling of terminal alkynes with arenediazonium salts has been developed. The arenediazonium salt synthesis/iododediazoniation/Sonogashira cross-coupling sequence can also be performed as a one-pot process, omitting the isolation of the arenediazonium salt.

Iron-catalysed Sonogashira Reactions

A catalytic system has been developed that used an iron/ligand combination for the Sonogashira cross coupling of terminal alkynes with aryl iodides, which affords products in good to excellent yields.

Synthesis of Indenes by the Transition Metal-Mediated Carboannulation of Alkynes

The synthesis of highly substituted indenes has been achieved by three different transition metal-mediated methods. The first method involves the palladium-catalyzed carboannulation of internal alkynes. The second method utilizes a two-step approach, which involves first the palladium/copper-catalyzed cross-coupling of terminal alkynes with appropriately functionalized aryl halides, followed by copper-catalyzed intramolecular cyclization. The third method involves intermolecular palladium-catalyzed arylation of the arylalkynes formed in the first step of the second method.

Cross‐Coupling of Arylboronic Acids with Terminal Alkynes in Air.

Abstract A new procedure has been developed for constructing arylalkynes through cross-coupling of terminal alkynes with arylboronic acids catalyzed by a palladium–silver system under mild conditions.

Cross-coupling of arylboronic acids with terminal alkynes in air

A new procedure has been developed for constructing arylalkynes through cross-coupling of terminal alkynes with arylboronic acids catalyzed by a palladium–silver system under mild conditions.