Propargyl Allenyl Research Articles

Synthesis of benzothiophene and indole derivatives through metal-free propargyl-allene rearrangement and allyl migration.

An efficient base-catalyzed protocol for the synthesis of benzothiophene is described. The reaction proceeds via base-promoted propargyl–allenyl rearrangement followed by cyclization and allyl migration. Phosphine-substituted indoles can be synthesized by a similar strategy.

Construction of highly functionalized thiophene and benzo[b]thiophene derivatives via a sequence of propargyl–allenyl isomerization/cyclization/demethylation

An efficient one-pot protocol for the synthesis of functionalized thiophene and benzo[b]thiophene derivatives was developed via a sequence of propargyl–allenyl isomerization/cyclization/demethylation. As a result of the readily accessible starting materials, simple operation, and mild conditions, this reaction should have potential utility in organic synthesis.

Angular-Shaped 4,10-Dialkylanthradiselenophene and Its Donor–Acceptor Conjugated Polymers: Synthesis, Physical, Transistor, and Photovoltaic Properties

An angular-shaped and isomerically pure 4,10-di(2-octyl)dodecylanthradiselenophene (aADS) was successfully developed. The expedient synthesis to form the framework of aADS with two lateral side chains regioselectively at its 4,10-positions is via a base-induced propargyl–allenyl isomerization/6π-electrocyclization/aromatization protocol. This pentacyclic distannylated aADS unit was then copolymerized with dithienyldiketopyrrolopyrrole (DPP) and dithienyl-5,6-difluoro-2,1,3-benzothiadiazole (DTFBT) acceptors with different alkyl side chains to afford four donor–acceptor copolymers: PaADSDPP, PaADSDTFBT-C4, PaADSDTFBT-C8, and PaADSDTFBT-C8C12. UV–vis spectroscopy and cyclic voltammetry revealed that PaADSDPP has the narrowest energy band gap, and PaADSDTFBT-C8C12 has larger band gap than PaADSDTFBT-C4 and PaADSDTFBT-C8. Two layer ONIOM (our own n-layered integrated molecular orbital and molecular mechanics) calculations were implemented to investigate the disparity in optical, electrochemical, and device pr...

ChemInform Abstract: Metal‐Free Synthesis of Polyfunctionalized 2,3‐Dihydropyrroles and Furans via the Sequence of Propargyl—Allenyl Isomerization and Alder Ene Reaction.

An efficient metal-free procedure for the synthesis of 4-diphenylphosphoryl)methyl-2,3-dihydro-1H-pyrroles and furans was developed via a sequence of propargyl–allenyl isomerization and Alder ene reaction. The Wittig-type olefination transformation of the phosphine oxide moiety to the vinyl group with high stereoselectivity was further investigated.

ChemInform Abstract: Synthesis of Cyclopentenes, Pyrroles, and Thiophenes via a Sequence of Propargyl—Allenyl Isomerizations, Michael Additions, and Intramolecular Wittig Reactions.

Allenylphosphonium species, reactive Michael acceptors, could be generated from simple, readily available propargylphosphonium salts through propargyl–allenyl isomerization. We developed an efficient synthesis for cyclopentenes, pyrroles, and thiophenes via a sequence of propargyl–allenyl isomerizations, Michael additions, and intramolecular Wittig reactions.

ChemInform Abstract: Synthesis of 1H‐Benzo[g]indazole Derivatives: Propargyl—Allenyl Isomerization and 6π‐Electrocyclization Involving Two Aromatic π‐Bonds.

Abstract An efficient synthesis of 1H-benzo[g]indazoles starting from Morita–Baylis–Hillman (MBH) adducts is disclosed. The synthesis was carried out from MBH bromide via a sequential copper-catalyzed alkynylation, one-pot synthesis of pyrazole, propargyl–allenyl isomerization, and a 6π-electrocyclization involving two aromatic π-bonds and an allenyl π-bond.

Metal-free synthesis of polyfunctionalized 2,3-dihydropyrroles and furans via the sequence of propargyl–allenyl isomerization and Alder ene reaction

An efficient metal-free procedure for the synthesis of 4-diphenylphosphoryl)methyl-2,3-dihydro-1H-pyrroles and furans was developed via a sequence of propargyl–allenyl isomerization and Alder ene reaction. The Wittig-type olefination transformation of the phosphine oxide moiety to the vinyl group with high stereoselectivity was further investigated.

Synthesis of 1H-benzo[g]indazole derivatives: propargyl–allenyl isomerization and 6π-electrocyclization involving two aromatic π-bonds

An efficient synthesis of 1H-benzo[g]indazoles starting from Morita–Baylis–Hillman (MBH) adducts is disclosed. The synthesis was carried out from MBH bromide via a sequential copper-catalyzed alkynylation, one-pot synthesis of pyrazole, propargyl–allenyl isomerization, and a 6π-electrocyclization involving two aromatic π-bonds and an allenyl π-bond.

ChemInform Abstract: Propargyl—Allenyl Isomerizations and Electrocyclizations for the Functionalization of Phosphonium Salts: One‐Pot Synthesis of Polysubstituted Vinylbenzenes and Naphthalenes.

ChemInform Abstract: Propargyl—Allenyl Isomerizations and Electrocyclizations for the Functionalization of Phosphonium Salts: One‐Pot Synthesis of Polysubstituted Vinylbenzenes and Naphthalenes.

Propargyl–Allenyl Isomerizations and Electrocyclizations for the Functionalization of Phosphonium Salts: One‐Pot Synthesis of Polysubstituted Vinylbenzenes and Naphthalenes

AbstractPhosphonium salts are widely used in organic synthesis as the precursor of Wittig reagents but highly functionalized phosphonium salts are not readily available. We have developed a sequence of propargyl–allenyl isomerizations and electrocyclizations for the functionalization of phosphonium salts via simple starting materials, which may provide an efficient one‐pot synthesis of polysubstituted vinylbenzenes and naphthalenes.magnified image

ChemInform Abstract: Synthesis of Polycyclic Isoindoline Derivatives via Tandem Pd‐Catalyzed Coupling, Propargyl—Allenyl Isomerization, [4 + 2] Cycloaddition and Aromatization Reaction.

AbstractA highly efficient, facile, and mild synthesis of the title compounds is developed from easily available starting materials.

ChemInform Abstract: Synthesis of Polyfunctionalized Quinolines via the Sequence of Propargyl—Allenyl Isomerization and Aza‐Electrocyclization.

AbstractThe derivative (VI) can smoothly be converted into the biologically important fused compound (VII).

ChemInform Abstract: Copper‐Catalyzed Tandem Alkynylation, Propargyl—Allenyl Isomerization, 6π‐Electrocyclization of Morita—Baylis—Hillman Adducts to Naphthalenes.

AbstractThe method renders possible an efficient synthesis of different naphthalene structures and related systems and can be conducted in one‐pot or in a stepwise manner.

Selective synthesis of allenyl aryl tellurides from diaryl ditellurides and propargyl bromide

Unsaturated tellurides are widely used in organic synthesis as intermediate products and synthons [1]. Cross coupling of vinyl tellurides underlay stereoselective syntheses of functionalized alkenes [1]. Development of new efficient procedures for the preparation of unsaturated tellurides containing both double [2, 3] and triple bond [4] from acetylene derivatives and nucleophilic [2] or electrophilic [3, 4] tellurium-containing reagents constitutes a line of our studies. Allenyl aryl selenides are generally prepared by isomerization of propargyl selenides under basic conditions [5]. Only a few data are available on the synthesis of allenyl aryl tellurides. Pourcelot [6] reported on the reaction of phenylchalcogenolate anions with propargyl bromide, which led to the formation of propargyl phenyl chalcogenides or mixtures of propargyl phenyl chalcogenides and allenyl phenyl chalcogenides. Following this procedure, allenyl phenyl telluride was synthesized in 27% yield. We have developed an efficient procedure for the synthesis of allenyl phenyl telluride (I) and previously unknown allenyl 4-tolyl telluride (II) in 90–93% yield from diaryl ditellurides and propargyl bromide (Scheme 1). The reaction was highly selective, and no aryl propargyl telluride was detected. Sodium tetrahydridoborate was gradually added to a solution of propargyl bromide and diaryl ditelluride in methanol at room temperature. The reduction of diaryl ditelluride with NaBH4 generates arenetellurolate anion which replaces the halogen atom in propargyl bromide. The reaction of diphenyl diselenide with propargyl bromide under analogous conditions gave 95% of phenyl propargyl selenide with high selectivity, while allenyl phenyl selenide was not detected. The spectral parameters of phenyl propargyl selenide were consistent with published data [5]. Selective formation of allenyl aryl tellurides indicates that the reaction follows 1,3-nucleophilic substitution pattern rather than usual 1,1-nucleophilic substitution that could lead to propargyl tellurides. Presumably, attack by bulky highly nucleophilic arenetellurolate anions on the terminal carbon atom at the triple bond is more favorable than on the carbon atom attached to halogen. In the former case, nucleophilic attack is accompanied by shift of electron density with simultaneous formation of allenyl fragment and bromide ion. ISSN 1070-4280, Russian Journal of Organic Chemistry, 2012, Vol. 48, No. 12, pp. 1569–1570. © Pleiades Publishing, Ltd., 2012. Original Russian Text © M.V. Musalova, M.V. Musalov, V.A. Potapov, S.V. Amosova, 2012, published in Zhurnal Organicheskoi Khimii, 2012, Vol. 48, No. 12, pp. 1598–1599.

Synthesis of Polycyclic Isoindoline Derivatives via Tandem Pd-Catalyzed Coupling, Propargyl–Allenyl Isomerization, [4 + 2] Cycloaddition and Aromatization Reaction

We report in this paper an interesting sequential reaction involving sequential Sonogashira coupling, propargyl-allenyl isomerization, [4 + 2] cycloaddition and aromatization reaction, which provides a facile method for the synthesis of a variety of polycyclic isoindoline derivatives from easily accessible starting materials.

Synthesis of Polyfunctionalized Quinolines via the Sequence of Propargyl–Allenyl Isomerization and Aza-electrocyclization

Quinoline derivatives are important heterocyclic compounds because of their natural occurrence and applications in pharmaceutical fields. In this paper, a sequence of propargyl-allenyl isomerization and aza-electrocyclization for the synthesis of polyfunctionalized quinolines are described.

Copper-catalyzed tandem alkynylation, propargyl–allenyl isomerization, 6π-electrocyclization of Morita–Baylis–Hillman adducts to naphthalenes

An expedient synthetic approach of naphthalenes was developed by the reaction of Morita–Baylis–Hillman bromides and arylacetylenes. The synthesis was carried out via a tandem copper-catalyzed alkynylation, propargyl–allenyl isomerization, and 6π-electrocyclization protocol.

3,3]-Sigmatropic Shifts and Retro-ene Rearrangements in Cyanates, Isocyanates, Thiocyanates, and Isothiocyanates of the Form RX-YCN and RX-NCY

Retro-ene type [2π + 2π + 2σ] and [3,3]-sigmatropic shift reactions involving the substituent groups R in heteroatom-substituted cyanates and thiocyanates RX-YCN and the isomeric isocyanates and isothiocyanates of the type RX-NCY (X = CR(2), NR', O, or S; Y = O or S) have been investigated computationally at the B3LYP/6-311++G(d,p) level. Retro-ene reactions of alkyl derivatives of the title compounds afford alkenes, imines, carbonyl and thiocarbonyl compounds together with HNCO (HNCS) or HOCN (HSCN). [3,3]-Sigmatropic shifts (hetero-Cope rearrangements) of the corresponding allyl, propargyl, benzyl, and aryl derivatives causes allylic rearrangements, propargyl-allenyl rearrangement, conversion of benzyl cyanates to o-isocyanatotoluenes, and conversion of N-cyanatoarylamines to o-isocyanatoanilines, etc. The corresponding rearrangements of allyl thiocyanates, arylamino thiocyanates and isothiocyanates, and arylsulfenyl thiocyanates and isothiocyanates are also described.

Palladium-catalyzed sequential reaction viaSonogashira coupling, isomerization, Claisen rearrangement and [4 + 2] cycloaddition sequence for the rapid synthesis of tricyclo[3.2.1.02,7]oct-3-ene derivatives

An interesting sequential reaction consisting of Sonogashira coupling, propargyl–allenyl isomerization, allenyl–benzyl Claisen rearrangement and [4 + 2] cycloaddition was developed. This reaction provides an efficient synthesis of fused tricyclo[3.2.1.02,7]oct-3-enes.

Sulfur-assisted propargyl–allenyl isomerizations and intramolecular cyclization for the synthesis of tricyclic thiophene derivatives

A facile and efficient cyclization for the synthesis of tricyclic thiophene derivatives was developed. As a metal-free process, a result of the ready availability of the starting materials and the simple and convenient operation, the type of reaction presented here has potential utility in organic synthesis.