A convenient scalable one-pot conversion of esters and Weinreb amides to terminal alkynes

Esters and amides undergo reduction to the corresponding aldehydes using DIBAL-H followed by same pot conversion to terminal alkynes utilizing the Bestmann-Ohira reagent in good to excellent yields. Additionally chiral nonracemic substrates undergo this transformation with complete preservation of stereochemical integrity.     

Visible-light promoted one-pot synthesis of pyrazoles from alkynes and hydrazines

A visible-light promoted cascade of Glaser coupling/annulation has been developed for one-pot synthesis of polysubstituted pyrazoles from alkynes and hydrazines. The method features mild reaction conditions, readily availible starting materials and green oxidant (O₂). It works for a wide range of substituted phenyl acetylene and hyrazines with good functional group tolerance and efficiency. Mechanistic pathways including photochemical irridiation, intramolecular hydrogen-atom-abstraction (HAT) and enamine-to-imine tautomerization was proposed for the transformation.     

Ruthenium-catalyzed oxidation of alkynes to 1,2-diketones under room temperature and one-pot synthesis of quinoxalines

A ruthenium-catalyzed alkyne oxidation to 1,2-diketones using Oxone under room temperature is reported. Both substrate scope and mechanism were discussed. Notably, combination of the alkyne oxidation and condensation cyclization in one pot offers a very efficient and convenient entry into quinoxaline derivatives.     

Synthesis of quinoxalines through iodine-catalyzed one-pot annulation of alkynes with o-phenylenediamines

The synthesis of N-heterocycles of quinoxalines has been developed by an efficient protocol of one-pot annulation of alkynes with o-phenylenediamines. A variety of quinoxalines were prepared in good to high yields in the presence of catalytic amount of iodine as a catalyst.     

Highly stereoselective one-pot procedure to prepare bis- and tris-chalcogenide alkenes via addition of disulfides and diselenides to terminal alkynes

We present here the reaction of diorganoyl dichalcogenides with terminal alkynes under catalyst-free conditions, by a one-pot procedure, to prepare bis- and tris-chalcogenide alkenes selectively, avoiding the previous preparation of chalcogen alkynes. The reaction proceeded cleanly under mild reaction conditions, and the addition of dichalcogenides to alkynes occurred stereoselectively to give exclusively the corresponding Z isomers. We observed that the selectivity control was governed by the effective participation of the hydroxyl group from propargyl alcohols. In addition, the bis-chalcogenide alkenes were exclusively obtained with propargyl alcohol having the acidic hydroxyl group proton. Conversely, the alkynes with no potentially acidic hydroxyl group proton, at propargyl positions, gave exclusively the tris-chalcogenide alkenes.     

Palladium-catalyzed coupling reaction of terminal alkynes with aryl iodides in the presence of indium tribromide and its application to a one-pot synthesis of 2-phenylindole

The use of a novel PdCl(2)(PPh(3))(2)-InBr(3) reagent system to catalyze cross-coupling reactions of a variety of aryl iodides with several terminal alkynes is described. The corresponding functional alkyne derivatives were produced in good to excellent yields. Moreover, a catalytic amount of InBr(3) effectively catalyzes the intramolecular cycloaddition of 2-phenylethynylaniline to form an indole skeleton in high yield.     

过渡金属促进的从三种不同的炔烃高效合成苯衍 生物的策略

报道利用过渡金属有机化合物(二茂锆和有机铜化合物),从三种不同的炔烃,如何实现了高选择性高产率并且一锅煮地合成苯衍生物。     

Microwave-assisted one-pot three-component polymerization of alkynes,aldehydes and amines toward amino-functionalized optoelectronic polymers

We present a microwave-assisted one-pot polymerization with three-components of alkynes, aldehydes and amines for the synthesis of new amino-functionalized optoelectronic polymers. The polymerization of diynes(1a-1c), dialdehydes(2a and 2b) and dibenzylamine catalyzed by InCl_3 was carried out smoothly within 1h under microwave radiation, yielding four soluble polymers with high molecular weights. The resulting polymers P1 and P2 could be easily dissolved in alcohol and thus utilized as the cathode interlayer for polymer solar cells(PSCs). Compared with the control device, the PSCs with P1 and P2 as the cathode interlayer and PTB7-Th:PC_(71)BM as the photoactive layer exhibited significantly higher power conversion efficiencies(PCEs) of 9.49% and 9.16%, respectively. These results suggest that this polycoupling reaction is an efficient approach to construct three-component polymers for the practical applications.     

Rhodium-catalyzed one-pot synthesis of substituted pyridine derivatives from alpha,beta-unsaturated ketoximes and alkynes

A rhodium-catalyzed chelation-assisted C-H activation of alpha,beta-unsaturated ketoximes and the reaction with alkynes to afford highly substituted pyridine derivatives is described.     

Enhancing regiocontrol in carboaluminations of terminal alkynes. Application to the one-pot synthesis of coenzyme Q10

Two new "generations" of methodological advances are reported for the Negishi carboalumination of terminal alkynes. Use of simple, inexpensive additives that alter the Al-Zr complex formed between Me(3)Al and Cp(2)ZrCl(2) give rise to an especially effective reagent mix that results in virtually complete control of regiochemistry upon carboalumination of 1-alkynes. One timely application to coenzyme Q10 is highlighted. Regioisomers from subsequent coupling, which would otherwise be very difficult to separate, are avoided.     

Direct application of gold nanoparticles to one-pot electrochemical biosensors

Gold nanoparticles (AuNPs) have been widely employed for the fabrication of electrochemical biosensors. In most cases, AuNPs are immobilized on the surface of an electrode, so they are difficult to be regenerated, making the use of the biosensor unfriendly. In this work, by adopting AuNPs directly as the electrolytes, we have developed a novel AuNPs-based electrochemical detection system. In brief, AuNPs-catalyzed oxidation of glucose is combined with a HRP-catalyzed reaction as well as an electrocatalytic reaction to compose cascade reactions in the electrolyte. Thus, the intensity of the electrocatalytic signals has quantitative relation with the concentration of glucose, and favors the sensitive detection of glucose. Furthermore, because the catalysis of AuNPs may be blocked under the interaction with single-stranded DNA and unblocked in the presence of a complementary sequence, detection of DNA and even single-nucleotide polymorphism can thereby been achieved. This one-pot detection system can be operated and regenerated very easily, since all the components are integrated in the electrolytes of AuNPs, and the unmodified electrode can be reused after being rinsed. This concept by integrating the advantages of sensitive electrochemical detection with the easy-to-operate nanocolloidal system may also promote the development of other kinds of electrochemical biosensors.     

Iron-catalyzed aryl- and alkenyllithiation of alkynes and its application to benzosilole synthesis

Phenyl- and vinyllithiums having an alkyl substituent at their ortho- and cis-position, respectively, readily added to alkynes in the presence of 5 mol% of Fe(acac)(3). The reaction of o-(trimethylsilyl)phenyllithium with alkynes gave benzosiloles through an addition-cyclization sequence.     

Synthesis of internal alkynes via one-pot palladium-catalyzed and dehydrobromination reactions of 1,1-dibromo-1-alkenes

Tandem palladium-catalyzed cross-coupling of alkyl, alkenyl, alkynyl, aryl, and heteroaryl 2-substituted 1,1-dibromo-1-alkenes with aryl or heteroaryl boronic acids or borate esters and dehydrobromination of the intermediate coupled products afforded internal alkynes in moderate to good yields (up to 89%). The synthesis has been carried out in a one-pot process and in a two-step sequence according to the nature of the starting 1,1-dibromoalkenes. The reported protocol is compatible with the presence in the 1,1-dibromo-1-alkene molecule of additional reactive halogen–carbon bonds, thus allowing to build up more complex alkyne derivatives.     

A novel three-component one-pot reaction involving alkynes, urea or thiourea, and aldehydes

A novel three-component, one-pot condensation yielding 2-amino-4H-1,3-oxazines or 2-amino-4H-1,3-thiazines from alkynes, urea or thiourea, and aldehydes is described. [reaction: see text]     

Preparation of diynes via selective bisalkynylation of zirconacycles

Reaction of alkynyl halides with in situ prepared zirconacyclopentanes, -pentenes, and -pentadienes in the presence of CuCl under mild reaction conditions afforded alkynes or diynes. Control of the reaction conditions selectively afforded monoalkynylation products of zirconacycles. Reaction of zirconacycles with 2 equiv of alkynyl halides resulted in the formation of diynes. Selective monoalkynylation of zirconacycle with an alkynyl halide, followed by reaction with a different alkynyl halide, afforded unsymmetrical diynes. Bisalkynylation product of zirconacyclopentadiene was gradually converted into a tricyclic compound.     

Trans-hydrometalation of alkynes by a combination of InCl3 and DIBAL-H: one-pot access to functionalized (Z)-alkenes

[reaction: see text] Triethylborane-induced hydrometalation of alkynes proceeds in an anti manner to afford the corresponding (Z)-alkenylmetal compounds stereoselectively, where dichloroindium hydride would play a key role. A variety of functional groups including hydroxy, carbonyl, and carboxy groups were tolerant under the reaction conditions. Following iodolysis and cross-coupling reaction of the (Z)-alkenylmetal species show the usefulness of this strategy.     

Copper-catalyzed one-pot synthesis of tetrasubstituted pyrazoles from sulfonyl azides,terminal alkynes,and hydrazonoyl chlorides

Ketenimine intermediates generated by the addition of copper acetylides to sulfonyl azides are trapped by nitrile imines (generated from hydrazonoyl chlorides and triethylamine) to afford tetrasubstituted pyrazoles in moderate to good yields.     

Convenient one-pot syntheses of 1,2-dithiole-3-thiones and 3-imino-1,2-dithioles from terminal alkynes

The reaction of acetylide anions with carbon disulfide or phenyl isothiocyanate followed by addition of sulfur in the presence of a protonating agent such as a primary amine or alcohol affords 1,2-dithiole-3-thiones or 3-imino-1,2-dithioles in good to excellent yields.     

Copper-catalyzed boration of activated alkynes. Chiral boranes via a one-pot copper-catalyzed boration and reduction protocol

Phosphine–copper(I) complexes efficiently catalyzed the mono-boration of electron-deficient alkynes in the presence of MeOH and also catalyzed conjugate reductions of alkenylboronates bearing an electron-withdrawing group. The mono-addition of bis(pinacolato)diboron to alkynes catalyzed by a copper–Xantphos complex produced vinylboronates with high regio and stereoselectivity and asymmetric reduction of the vinylboronates by a chiral copper–bisphosphine catalyst allowed the synthesis of valuable chiral boranes with high enantioselectivity. One-pot boration/asymmetric reduction of α,β-unsaturated alkynoates could be conducted with a single copper–phosphine catalyst.