An efficient synthesis of 6-formyl-1,2-dihydro-2-oxo-3-pyridinecarboxylic acid and some carbonyl derivatives of it and its 6-acetyl homologue

Starting with 1,1-dimethoxy-2-propanone ( 1 ), 6-formyl-1,2-dihydro-2-oxo-3-pyridinecarboxylic acid ( 5a ) has been prepared in large quantities by a highly efficient, 4-step synthesis. This compound, along with its one carbon homologue, 6-acetyl-1,2-dihydro-2-oxo-3-pyridinecarboxylic acid ( 5b ) has been reacted with several carbonyl derivative forming reagents to provide a series of side chains for β-lactams. Among these carbonyl derivatives are styrylamides which were prepared from Wittig and Horner-Emmons reagents. The preparation of the phosphonium salts and phosphonate esters is also described.     

Zwitterionic phosphonium sulfonates as easily phase-separable ion-tagged Wittig reagents

Zwitterionic phosphonium sulfonates 3, conveniently derived from TPPMS (1), can be used as Wittig reagents in solution. The excess reagents and byproduct TPPMSO (6) can be easily separated from the product alkenes by simple precipitation with a less polar solvent. The alkenes thus obtained were often sufficiently pure without chromatographic purification. A one-pot protocol for the synthesis of alpha,beta-unsaturated esters has been developed and appears to be convenient.     

Carbon-centered strong bases in phosphonium ionic liquids

Phosphonium ionic liquids (PhosILs), most notably tetradecyl(trihexyl)phosphonium decanoate (PhosIL-C(9)H(1)9COO), are solvents for bases such as Grignard reagents, isocyanides, Wittig reagents (phosphoranes), and N-heterocyclic carbenes (NHCs). The stability of the organometallic species in PhosIL solution is anion dependent. Small bases, such as hydroxide, react with the phosphonium ions and promote C-H exchange as suggested by deuterium-labeling studies. A method to dry and purify the ionic liquids is described and this step is important for the successful use of basic reagents in PhosIL. NHCs have been generated in PhosIL, and these persistent solutions catalyze organic transformations such as the benzoin condensation and the Kumada-Corriu cross-coupling reaction. Phosphoranes were generated in PhosIL, and their reactivity with various organic reagents was also tested. Inter-ion contacts involving tetraalkylphosphonium ions have been assessed, and the crystal structure of [(n-C(4)H(90)(4)P][CH(3)CO(2).CH(3)CO(2)H] has been determined to aid the discussion. Decomposition of organometallic compounds may also proceed through electron-transfer processes that, inter alia, may lead to decomposition of the IL, and hence the electrochemistry of some representative phosphonium and imidazolium ions has been studied. A radical derived from the electrochemical reduction of an imidazolium ion has been characterized by electron paramagnetic resonance spectroscopy.     

The behavior of 2‐substituted‐1,3‐diphenylpropane‐1,3‐tione toward organophosphorus reagents

The reaction of 2‐benzylidene‐1,3‐diphenylpropanetrione ( 1a ) with phosphorus ylides 2a–c afforded the new phosphonium ylides 4a–c . Trialkyl phosphites 3a–c react with 1a to give the respective dialkyl phosphonate products 5a–c . On the other hand, the olefinic compounds 6 and 7 were isolated from the reaction of 1b with Wittig reagents 2 . Moreover, trialkyl phosphites reacted with 1b to give products 8a–c . Possible reaction mechanisms are considered, and the structural assignments are based on analytical and spectroscopic evidence. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:57–64, 2000     

新型含取代乙烯基香豆素衍生物的合成及其光学性能

利用Perkin反应和Wittig反应设计并合成了两个新型的香豆素衍生物——3-(4’-溴苯基)-7-(N-辛基-3’-溴咔唑-6’-乙烯基)香豆素(6a)和3-(4’-溴苯基)-7-(4’-甲氧基苯基-1’-乙烯基)香豆素(6b),其结构经UV,1H NMR,IR,MS和荧光光谱表征。研究结果表明,6a和6b具有荧光强度大和Stokes位移(分别为115 nm和122 nm)大的特点。     

Stereoselective syntheses of the antihistaminic drug olopatadine and its E-isomer

Practical stereoselective synthetic routes to the antihistaminic drug olopatadine and its E-isomer have been developed, the key steps being a trans stereoselective Wittig olefination using a nonstabilized phosphorus ylide and a stereoselective Heck cyclization. The stereoselectivity of the Wittig reaction depends on both the phosphonium salt anion and the cation present in the base used to generate the ylide.     

The Four Isomeric 1,3,5-Undecatrienes. Synthesis and configurational assignment

The four geometrical isomers of 1,3,5-undecatriene, 1a–d have been prepared (stereospecifically and non-stereospecifically), using either (1) the Wittig reaction, (2) thermal sigmatropic hydrogen shifts, (3) partial reduction of triple bonds by zinc, or (4) organocopper reagents. The thermal behaviour of the four 1,3,5-undecatrienes has been investigated and the products formed have been characterized. The spectra of 1a–d, and of related compounds, have been discussed in order to corroborate their configurational assignment.     

Dipyrazolinyl-substituted 1,4-distyrylbenzenes

A number of dipyrazolinyl-substituted 1,4-distyryl- and 1,4-distyryl-2-methylbenzenes — new luminophores that have intense yellow-green luminescence — were obtained by the Wittig reaction by refluxing 1-(4-formylphenyl)-3-aryl-5-phenyl-2-pyrazolines and aromatic bisphosphonium salts in isopropyl alcohol in the presence of sodium isopropoxide. The low reactivities of the aldehydes used and the predominant formation of trans isomers in the Wittig reaction are noted. Data from the IR and electronic absorption spectra and the fluorescence spectra of the synthesized compounds are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 532–535, April, 1979.     

Total synthesis of the antitumor acetogenin mosin B: desymmetrization approach to the stereodivergent synthesis of threo/trans/erythro-type acetogenins

A total synthesis of the threo/trans/erythro-type acetogenin mosin B and one of its diastereomers has been achieved. The carbon skeleton is assembled in a convergent fashion from two segments (a THF ring segment and a gamma-lactone segment) through the Nozaki-Hiyama-Kishi reaction. The THF ring segment was stereoselectively constructed by a stereodivergent synthesis starting from a common intermediate (4-cyclohexene-1,2-diol) based on a desymmetrization strategy. The gamma-lactone segment was synthesized by coupling a triflate and a chiral alpha-sulfenyl gamma-lactone. By virtue of these synthetic results, we suggest that the absolute configuration of natural mosin B is 1 a. Antiproliferative effects of 1 a and 1 b were also investigated.     

Catalytic enantioselective pyrrole alkylations of alpha,beta-unsaturated 2-acyl imidazoles

[reaction: see text] Enantioselective additions of pyrroles to alpha,beta-unsaturated 2-acyl imidazoles catalyzed by the bis(oxazolinyl)pyridine-scandium(III) triflate complex (1) have been accomplished. The alpha,beta-unsaturated 2-acyl imidazoles were synthesized in high yields through Wittig olefination. A short, enantioselective synthesis of the alkaloid (+)-heliotridane has been accomplished utilizing this methodology and a 2-acyl imidazole cleavage and cyclization. This methodology was then extended to the one-pot asymmetric synthesis of 2-substituted indoles.     

Design of ionic liquids as a medium for the Grignard reaction

Design of novel phosphonium ionic liquids that are compatible with Grignard reagents have been investigated; several types of phosphonium salts that have an alkyl ether moiety have been synthesized and their capability evaluated as solvents for Grignard reagents. It has been established that even basic aliphatic Grignard reagent-mediated reactions are possible when methoxyethyl(tri-n-butyl)phosphonium bis(trifluoromethanesulfonyl)imide is used as the solvent.     

Rational Design 2-Hydroxypropylphosphonium Salts as Cancer Cell Mitochondria-Targeted Vectors: Synthesis,Structure, and Biological Properties

It has been shown for a wide range of epoxy compounds that their interaction with triphenylphosphonium triflate occurs with a high chemoselectivity and leads to the formation of (2-hydroxypropyl)triphenylphosphonium triflates 3 substituted in the 3-position with an alkoxy, alkylcarboxyl group, or halogen, which were isolated in a high yield. Using the methodology for the disclosure of epichlorohydrin with alcohols in the presence of boron trifluoride etherate, followed by the substitution of iodine for chlorine and treatment with triphenylphosphine, 2-hydroxypropyltriphenylphosphonium iodides 4 were also obtained. The molecular and supramolecular structure of the obtained phosphonium salts was established, and their high antitumor activity was revealed in relation to duodenal adenocarcinoma. The formation of liposomal systems based on phosphonium salt 3 and L-α-phosphatidylcholine (PC) was employed for improving the bioavailability and reducing the toxicity. They were produced by the thin film rehydration method and exhibited cytotoxic properties. This rational design of phosphonium salts 3 and 4 has promising potential of new vectors for targeted delivery into mitochondria of tumor cells.     

Comparing and taming the reactivity of HWE and Wittig reagents with cyclic hemiacetals

A practical solution to the formation of mixtures of E/Z and open/cyclic isomers in the reaction of (2R,4S)-4-hydroxy-2-methylpentanal (as its hemiacetal, a lactol) with conjugated phosphoranes (stabilised Wittig reagents) and Horner-Wadsworth-Emmons reagents is disclosed. The HWE reaction has a strong bias to give oxolanes. On the other hand, stabilised Wittig reagents give unsaturated carboxyl derivatives of configuration E (major) and oxolanes (minor); the latter can be avoided by addition of CF₃CH₂OH or using morpholine amide phosphorane.     

具有叶绿素-a碳架的苯乙烯基取代Z/E-二氢卟吩衍生物的合成

The Wittig reaction of methyl pyropheophorbide-d 2,obtained from methyl pyropheophorbide-a 1,with ben-zyltriphenylphosphonium bromide was performed to yield isomers 3a and 3b.The Vilsmeier reaction of nickelcomplex 4 or 7 with 3-dimethylaminoacrolein in the presence of phosphoryl chloride was carried out to form20-meso-2'-formylvinylpyropheophorbide-a 5 or 8,which was reacted with Wittig reagent to afford nickel complexisomers 6a and 6b or 9a and 9b,10a and 10b.     

Radical-mediated anti-Markovnikov hydrophosphonation of olefins

The radical-mediated addition of triphenylphosphonium tetrafluoroborate to olefins (hydrophosphonation) is reported. Both standard radical initiators and photochemical conditions are effective, up to the gram scale. The phosphonium salts are shown to serve as Z-selective Wittig olefination reagents, even without purification.     

The reaction of Wittig and Wittig–Horner reagents with dicyanomethylene derivatives of fluorenone,xanthone, and thiaxanthone. A novel synthesis of phosphoranylidenecyclobutylidene derivatives

>Wittig reagents 1a,b react with dicyanomethylene derivatives of fluorenone (3) and xanthone (4) to give the corresponding phosphoranylidenecyclobutylidene adducts 6a, 6b, 9a, and 9b. On the other hand, the reaction of Wittig–Horner reagents (2) with the same nitriles 3 and 4 afforded the respective phosphonate adduct 8 and the alkylated product 10. A mechanism that accounts for the formation of the new products is presented. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 263–269, 1999     

The Mechanism and Stereochemistry of Wittig Reactions of Phosphonium Ylide-Anions

Abstract

Schmidbaur's group have extensively investigated¹ the coordination properties of phosphonium 1,3-ylide-anions (1) in organometallic chemistry and more recently Cristau² has reported the potential usefulness of these compounds in synthetic organic chemistry. There have been a few studies³ of specific phosphonium 1,1-ylide-anions (2), however their only use in the Wittig reaction appears to be that of (2a).⁴ We have set out to study the stereochemistry and mechanism of Wittig reactions of (1) and (2) and to carry out some preliminary investigations on the arsenic analogues (3).     

Preparation and chemistry of phosphoranyl-derived iodanes

The preparation and chemistry of novel phosphoranyl-derived lambda(3)-iodanes is reported. The phosphoranyl-derived phenyliodonium sulfonates were prepared in good yields by the reaction of stabilized phosphonium ylides [1-triphenylphosphoranylidene-2-propanone, methyl(triphenylphosphoranylidene)acetate, (triphenylphosphoranylidene)acetaldehyde, and (triphenylphosphoranylidene)acetonitrile] with the pyridinium complex of iodobenzene ditriflate or with [hydroxy(tosyloxy)iodo]benzene under mild conditions. These compounds represent a potentially useful class of reagents that combine in one molecule synthetic advantages of a phosphonium ylide and an iodonium salt. Specifically, phosphorane-derived phenyliodonium tosylates can react with soft nucleophiles, such as iodide, bromide, benzenesulfinate, and thiophenolate anions, with a selective formation of the respective alpha-functionalized phosphonium ylides, which can be further converted to alkenes by the Wittig reaction with benzaldehyde. The phosphoranyl-derived benziodoxoles can be prepared by the reaction of 1-acetoxybenziodoxole with stabilized phosphonium ylides. An unusual ligand exchange on the iodine(III) center resulting in the substitution of a carbon ligand with an oxygen ligand was observed in the reaction of these compounds with strong acids.     

Scope and Limitation of the Reactions of 3-Imino Derivatives of Pentane-2,4-Diones with Organophosphorus Reagents

Abstract

3-(Hydroxyimino)pentane-2,4-dione reacts with phosphonium ylides, Wittig–Horner reagents, trialkyl phosphites, and Lawesson's reagents to give the olefinic and cyclic products, the phosphonate adducts, the dialkyl phosphate products, the phosphinodithioic acid, and 2,4-dithione products, respectively. Furthermore, the reaction of 3-(phenylimino)pentane-2,4-dione with Wittig, Wittig–Horner reagents and trialkyl phosphite resulted in the formation of 2,5-diendioate, diethoxy phosphoryl hexanoate and the phosphate products. Possible reaction mechanisms are considered and the structural assignments are based on analytical and spectroscopic results. The antibacterial and antifungal activities for some of the new compounds are also reported.     

Stereoselective Synthesis of （Z）-5-（Trideca-4-enyl）resorcinol and Gibbilimbols A-D

(Z)-5-(Trideca-4-enyl)resorcinol (1) and gibbilimbols A-D(2-5) were synthesized in 47%-60% yields over 6 steps from commercially available starting materials. The Wittig reaction of various alkyl phosphonium bromides with appropriate aldehydes in the presence of potassium tert-butoxide (t-BuOK) in anhydrous THF solution at room temperature served as the key step, and the result showed that only (Z)-configuration olefins were formed by this procedure. The synthesis of the (Z)-5-(trideca-4-enyl)resorcinol (1) was reported for the first time.