Intramolecular Wittig Reaction Research Articles

Vinylphosphonium and 2-aminovinylphosphonium salts - preparation and applications in organic synthesis.

The main synthetic routes towards vinylphosphonium salts and their wide applications in organic synthesis are discussed in this review. Particular attention is paid to the use of these compounds as building blocks for the synthesis of carbo- and heterocyclic systems after their prior transformation into the corresponding phosphorus ylides, followed by the intramolecular Wittig reaction with various types of nucleophiles containing a carbonyl function in their structures.

A facile and regioselective one-pot synthesis of novel pyrazolo[1[Formula: see text],5[Formula: see text]:1,2]pyrrolo[3,4-b]quinoline-2,3-dicarboxylate hybrids via intramolecular Wittig reaction.

The regioselective syntheses of novel pyrazolo[1[Formula: see text],5[Formula: see text]:1,2]pyrrolo[3,4-b]quinoline-2,3-dicarboxylates (6a-l) from pyrrolo([3,4-b]quinolin-2(3H)-yl)benzamides through an intramolecular Wittig reaction are described. This protocol takes advantages of mild conditions, simple workup and high yield which make this method attractive for the synthesis of these hybrid of pyrazolo[1[Formula: see text],5[Formula: see text]:1,2]pyrrolo[3,4-b]quinolines.

Divergent Access to 1-Naphthols and Isocoumarins via Rh(III)-Catalyzed C-H Activation Assisted by Phosphonium Ylide.

Rh-catalyzed C-H activation of phenacyl phosphoniums in coupling with α-diazocarbonyl compounds has been realized with the assistance of a mutifunctional phosphonium ylidic directing group, providing expedient accesses to 1-naphthols and isocoumarins. Switchable synthesis of 1-naphthols and isocoumarins was realized by substrate control, where these transformations were enabled by initial C-H activation and subsequent intramolecular Wittig reaction or nucleophilic C-O formation.

Catalytic Intramolecular Wittig Reaction Based on a Phosphine/Phosphine Oxide Catalytic Cycle for the Synthesis of Heterocycles

The catalytic intramolecular Wittig reactions of carbonyl‐containing bromides are reported. The R3PO byproducts participate in the catalytic cycle; therefore, the Wittig reaction can be accomplished with only a catalytic amount of organophosphorus reagent. The reaction has also been applied to the efficient and selective synthesis of isoquinolin‐1(2H)‐ones, indoles, 2,3‐dihydro‐1H‐2‐benzazepin‐1‐ones, benzofurans, and 1,2‐dihydroquinolines with a catalytic amount of phosphine oxide (0.1 equiv.) and a tetramethyldisiloxane/titanium isopropoxide [TMDS/Ti(OiPr)4] reductant system (yields: 35–88 %).

Diversity Oriented Synthesis of Natural 2‐Arylbenzofuran, Moracin F

Diversity oriented synthesis of natural 2‐arylbenzofuran, moracin F (1) has been carried out from the commercially available starting materials using Sonogashira coupling, Suzuki coupling, neutral Al2O3 mediated cyclization, and intramolecular Wittig reaction as key steps.

Synthesis of Functionalized Furans via Chemoselective Reduction/Wittig Reaction Using Catalytic Triethylamine and Phosphine

An efficient protocol for the synthesis of highly functionalized furans via intramolecular Wittig reaction has been developed using catalytic amounts of phosphine and triethylamine. Silyl chloride served as the initial promoter to activate the phosphine oxide. Reduction of the activated phosphine oxide by hydrosilane resulted in generation of phosphine, while decomposition of Et3N·HCl resulted in regeneration of base, which mediated formation of phosphorus ylide. Remarkably, the in situ generated byproduct, Et3N·HCl, also catalyzes reduction of phosphine oxide.

One-Pot Synthesis of Tetraphene and Construction of Expanded Conjugated Aromatics.

Acene derivatives as a class of polycyclic aromatic hydrocarbons have attracted considerable interest because of their outstanding semiconductor properties. We developed a one-pot synthesis for fully conjugated tetraphene via a sequence of propargyl-allenyl isomerization, phosphine addition, intramolecular Wittig reactions, and Diels-Alder cyclization reactions. The derivative-conjugated aromatic compounds including carbazole or triphenylamine have been constructed via Pd-catalyzed coupling reaction with dibromotetraphene. These compounds show superior photophysical and electrochemical properties, which make them possible candidates for optoelectronic conjugated materials.

ChemInform Abstract: One‐Pot Synthesis of 1H‐Isochromenes and 1,2‐Dihydroisoquinolines by a Sequential Isocyanide‐Based Multicomponent/Wittig Reaction.

AbstractPasserini or Ugi condensations, coupled with an intramolecular Wittig reaction give access to the title compounds.

“β-Cyclodextrin nano-reactor”-catalyzed synthesis of 2H-chromene-2,3-dicarboxylates from in-situ-generated stabilized phosphorus ylides via intramolecular Wittig reaction in water

GRAPHICAL ABSTRACT

ChemInform Abstract: One‐Pot Synthesis of Isoquinolin‐1(2H)‐ones by a Sequential Ugi 4CC/Wittig Process.

A one-pot synthetic approach to isoquinolin-1(2H)-ones through a Ugi/Wittig sequence has been developed. The reaction of phosphonium salt, aldehyde, secondary amine, and isocyanide produced isoquinolin-1(2H)-ones in good yields through sequential Ugi condensation and intramolecular Wittig reaction in the presence of K2CO3.

One-Pot Synthesis of Isoquinolin-1(2H)-ones by a Sequential Ugi 4CC/Wittig Process

A one-pot synthetic approach to isoquinolin-1(2<i>H</i>)-ones through a Ugi/Wittig sequence has been developed. The reaction of phosphonium salt, aldehyde, secondary amine, and isocyanide produced isoquinolin-1(2<i>H</i>)-ones in good yields through sequential Ugi condensation and intramolecular Wittig reaction in the presence of K₂CO₃.

Computational study on the mechanism of the three-component reaction of dimethylacetylene dicarboxylate and triphenylphosphine with 2-acetylbutyrolactone

The molecular mechanism of the three-component reaction of triphenylphosphine, dialkyl acetylene dicarboxylate, and 2-acetylbutyrolactone to synthesize the stabilized phosphorus ylide and 1,3-butadiene derivative via the intramolecular Wittig reaction has been investigated using the density functional theory method at the B3LYP/6-31G level of theory. Two possible reaction pathways have been characterized in detail to form the cyclobutene intermediate and in the next step; the cyclobutene intermediate undergoes the conrotatory ring-opening reaction to produce the 1,3-butadiene derivative along two possible pathways. The calculated results indicate that two pathways (pathways II and II-a) are the most energy favorable among all of the pathways, so they occur more than do the others. Moreover, the phosphorus ylide is more stable than the corresponding 1,3-butadiene, demonstrating that the intramolecular Wittig reaction could not easily occur at room temperature, which is in agreement with the experimental results.

ChemInform Abstract: Synthesis of 2,3‐Dihydro‐1H‐2‐benzazepin‐1‐ones and 3H‐2‐Benzoxepin‐1‐ones by Isocyanide‐Based Multicomponent Reaction/Wittig Sequence Starting from Phosphonium Salt Precursors.

AbstractThe reactions of phosphonium salts, arylglyoxals, amines, and isocyanides give dihydrobenzazepinones in good yields via a sequential Ugi condensation and intramolecular Wittig reaction.

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: A Practical One‐Pot Synthesis of Coumarins in Aqueous Sodium Bicarbonate via Intramolecular Wittig Reaction at Room Temperature.

AbstractThe reaction can be scaled up.

Synthesis, structure, and properties of the product formed in the reaction of ortho-diphenylphosphinobenzaldehyde and N-tosyl-1,2-phenylenediamine

Interaction of ortho-diphenylphosphinobenzaldehyde with N-tosyl-1,2-phenylenediamine afforded the product of intramolecular Wittig reaction, N-{2-[2-(Diphenylphosphoryl)benzylamino]phenyl}-4-methylbenzenesulfonamide. Its structure was established on the basis of IR, 1H NMR, 13C NMR, and 2D 1H NMR (COSY) spectroscopy. Reaction mechanism was studied by means of quantum chemistry DFT method. Complexforming property of the obtained diphenylphosphine oxide was investigated.

Construction of the [6-7-5-5] tetracyclic core of all the carbocyclic frameworks of yuzurimine-type alkaloids.

Yuzurimine-type alkaloids make up a sub-family of Daphniphyllum alkaloids structurally featuring a [6-7-5-5] tetracarbocyclic core framework. In this manuscript, we describe our construction of the [6-7-5-5] tetracarbocyclic core of yuzurimine-type alkaloids by using a unique in situ intramolecular Wittig reaction and Sm-mediated cyclization as key steps.

Synthesis of 2,3-Dihydro-1H-2-benzazepin-1-ones and 3H-2-Benzoxepin-1-ones by Isocyanide-Based Multicomponent Reaction/Wittig Sequence Starting from Phosphonium Salt Precursors.

A one-pot synthesis of multisubstituted 2,3-dihydro-1H-2-benzazepin-1-ones and 3H-2-benzoxepin-1-ones by an I-MCR/Wittig sequence was developed. The reaction of phosphonium salt 3, arylglyoxals 4, amine 5 (or without), and isocyanide 6 produced the 2,3-dihydro-1H-2-benzazepin-1-ones 8 or 3H-2-benzoxepin-1-ones 10 in good yields via a sequential Ugi or Passerini condensation and intramolecular Wittig reaction in the presence of NEt3.

Chemoselective intramolecular Wittig reactions for the synthesis of oxazoles and benzofurans.

A chemoselective approach was developed for the synthesis of highly functionalized oxazoles and benzofurans using an intramolecular Wittig reaction as the key step. By choosing proper trapping reagent or method of addition of reagents, chemoselectivity can be controlled toward either oxazole or benzofuran derivatives.

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.