Pyridinium Methylides Research Articles

Synthesis of indolizines from n-(2,2,2-trifluoroethyl)pyridinium triflate; evidence for the generation of pyridinium (trifluoromethyl)methylide

Dimethyl 3-(trifluoromethyl)indolizine-1,2-dicarboxylate (4), 1,2,3-tris(trifluoromethyl)indolizine (5), and ethyl trans -2,3-bis(trifluoromethyl)-2,3-dihydroindolizine-1-carboxylate (7) have been obtained via treatment of N-(2,2,2-trifluoroethyl)pyridinium triflate (2) with a base (B) and dimethyl acetylenedicarboxylate [→ 4 (B = Et 3N)] or perfluorobut-2-yne [→ 5 (B = K 2CO 3); → 7 (B = Et 3N)]. Correct elemental analyses [C,H,F and N except in the case of the triflate (2), where F was not determined] and spectroscopic data (i.r., n.m.r., mass) consistent with structures assigned were obtained for compounds 2, 4, 5 and 7. The structure of the dihydroindolizine (7) was established absolutely by X-ray crystallography, the analysis being carried out by Dr. R. G. Pritchard (UMIST), to whom we are extremely grateful. We are also indebted to the Iraqi Ministry of Higher Education and Science for the award of a Scholarship (to. S. N. M.).

ChemInform Abstract: Cycloaddition of Pyridinium Methylides with Electron‐Deficient Olefins and Silica‐Gel Mediated Elimination of Pyridines from the Cycloadducts: A New Method of Alkylation or Hydroalkylidenation of Olefins.

ChemInformVolume 18, Issue 35 Preparative Organic Chemistry ChemInform Abstract: Cycloaddition of Pyridinium Methylides with Electron-Deficient Olefins and Silica-Gel Mediated Elimination of Pyridines from the Cycloadducts: A New Method of Alkylation or Hydroalkylidenation of Olefins. O. TSUGE, O. TSUGE Dep. Mol. Sci. Technol., Kyushu Univ., Kasuga 816Search for more papers by this authorS. KANEMASA, S. KANEMASA Dep. Mol. Sci. Technol., Kyushu Univ., Kasuga 816Search for more papers by this authorS. TAKENAKA, S. TAKENAKA Dep. Mol. Sci. Technol., Kyushu Univ., Kasuga 816Search for more papers by this author O. TSUGE, O. TSUGE Dep. Mol. Sci. Technol., Kyushu Univ., Kasuga 816Search for more papers by this authorS. KANEMASA, S. KANEMASA Dep. Mol. Sci. Technol., Kyushu Univ., Kasuga 816Search for more papers by this authorS. TAKENAKA, S. TAKENAKA Dep. Mol. Sci. Technol., Kyushu Univ., Kasuga 816Search for more papers by this author First published: September 1, 1987 https://doi.org/10.1002/chin.198735132Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume18, Issue35September 1, 1987 RelatedInformation

ChemInform Abstract: Synthesis of Indolizines from Pyridinium (Trifluoroacetyl)methylide and Fluorinated Dipolarophiles.

AbstractThe indolizine derivatives (III) and the 1‐azaindolizine (V) are synthesized by coupling the trifluoroacetylmethylide (I) with the unsaturated compounds (II) or the nitrile (IV).

Cycloaddition of Pyridinium Methylides with Electron-Deficient Olefins and Silica-Gel Mediated Elimination of Pyridines from the Cycloadducts: A New Method of Alkylation or Hydroalkylidenation of Olefins

Abstract Pyridinium methylides bearing an anion-stabilizing substituent at the ylide carbon react with a variety of olefins carrying two electron-withdrawing groups at the both carbons such as N-substituted maleimides, a citraconimide, dimethyl maleate, dimethyl fumarate, and 1,2-dibenzoylethene. The cycloadducts thus formed undergo a ready elimination of pyridines when treated with silica gel. This sequence is a new method for alkylation or hydroalkylidenation of olefins.

Synthesis of indolizines from pyridinium(trifluoroacetyl)methylide and fluorinated dipolarophiles

Abstract Some new fluoroindolizines have been synthesised via 1,3-cycloaddition reactions between pyridinium (trifluoroacetyl)methylide (I) and fluorinated dipolarophiles [CF 3 CN→(II); CF 3 CCCF 3 →(III) (mainly) + (IV) and (V); CF 3 CCH→(VI); CF 3 CFCF 2 → (VII)] and dimethyl acetylenedicarboxylate [→(VIII)]. Treatment of (III) with base converted it to (IX).

Stereoselective synthesis of hexa- and tetrahydroindolizin-7-ones through cycloaddition of pyridinium methylides

Cycloadditions dipolaires 1,3 de t-butyldimethylsiloxy α-R pyridiniomethanures (R=benzoyl, cyano, methoxycarbonyl) avec des composes vinyliques ou acetyleniques deficients en electrons: obtention d'hexahydro-1,2,3,7,8,8a- et tetrahydro-1,7,8,8a indolizinones-7 substituees -1,3 et -1,2,3

ChemInform Abstract: N‐(TRIMETHYLSILYLMETHYL)PYRIDINIUM TRIFLUOROMETHANESULFONATES AS FACILE PRECURSORS FOR NONSTABILIZED PYRIDINIUM METHYLIDES

Chemischer InformationsdienstVolume 15, Issue 32 Heterocyclic Compounds ChemInform Abstract: N-(TRIMETHYLSILYLMETHYL)PYRIDINIUM TRIFLUOROMETHANESULFONATES AS FACILE PRECURSORS FOR NONSTABILIZED PYRIDINIUM METHYLIDES O. TSUGE, O. TSUGESearch for more papers by this authorS. KANEMASA, S. KANEMASASearch for more papers by this authorS. KURAOKA, S. KURAOKASearch for more papers by this authorS. TAKENAKA, S. TAKENAKASearch for more papers by this author O. TSUGE, O. TSUGESearch for more papers by this authorS. KANEMASA, S. KANEMASASearch for more papers by this authorS. KURAOKA, S. KURAOKASearch for more papers by this authorS. TAKENAKA, S. TAKENAKASearch for more papers by this author First published: August 7, 1984 https://doi.org/10.1002/chin.198432231AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume15, Issue32August 7, 1984 RelatedInformation

STEREOSELECTIVE HYDROALKYLIDENATION OF OLEFIN WITH PYRIDINIUM METHYLIDES

Abstract Acid-catalyzed elimination of pyridine from the stereoselective [3+2] cycloadducts between electron-deficient olefins and pyridinium methylides with ylide-stabilizing substituents offers a new type of C–C bond formation.

NEW C–C BOND FORMATION WITH PYRIDINIUM METHYLIDE: HYDROMETHYLENATION OF OLEFIN

Abstract New C–C bond formation with pyridinium methylide is presented: Pyridinium methylide reacts with electron-deficient olefins providing the next higher homologs of olefins, in which the double bond of starting olefin is saturated and, instead, a C=C double bond is newly formed. This reaction mode has been never reported before in the study of nitrogen ylide and is to be referred to as hydromethylenation of olefin. In the presence of base, 1,2-double bond migration occurs leading to the methylated derivatives of starting olefins.

N-(TRIMETHYLSILYLMETHYL) PYRIDINIUM TRIFLUOROMETHANESULFONATES AS FACILE PRECURSORS FOR NONSTABIL1ZED PYRID1NIUM METHYLIDES

As facile precursors for nonstabilized pyridinium methylides N-(trimethylsilylmethyl)pyridinium triflates were synthesized. Cesium fluoride induced desilylation of the precursors liberated the nonstabilized pyridinium methylides which were trapped as the cycloadducts to dimethyl acetylenedicarboxylate.

Reaction of 2,2-dimethyl-1,3-dioxin-4-one derivatives with pyridinium (isoquinolinium) methylides and cyano compounds.

Cycloaddition of acylketenes (2) to 1, 2-and 1, 3-dipolar compounds was investigated. The thermal reaction of 1, 3-dioxin-4-ones (1) with isoquinolinium phenacylide (11) gave the aromatized pyrrolo [2, 1-a] isoquinolines (12-15). The reaction of 1 with pyridinium and isoquinolinium cyanomethylides (3-5) afforded the 1, 3-oxazinylmethylides (6-8). The intermediate 2 likewise reacted with cyanamides and benzonitriles to give the corresponding 1, 3-oxazin-4-one derivatives (19-23).

Reactions of pyridinium t-butoxycarbonylmethylide with perfluoropropene and some fluoroaromatics

▪ Perfluorotoluene, pentafluoropyridine, 3-chlorotetrafluoropyridine, and 3,5-dichlorotrifluoropyridine react with pyridinium t-butoxycarbonylmethylide (I) in acetonitrile at 0 – 20 °C to yield, via nucleophilic displacement of a 4-F substituent in each case, the new pyridinium methylides (II)–(V), respectively. Treatment of perfluoropropene with (I) gives 1-(t-butoxycarbonyl)-2-fluoro-3-(trifluoromethyl)- pyrrolo[1,2- a ]pyridine (VI) and 1,3-bis(t-butoxycarbonyl)-2- (1,2,2,2-tetrafluoroethyl)pyrrolo[1,2- a ]pyridine (VII), formation of the latter (minor) product providing evidence that the former arises via a stepwise dipolar cycloaddition. ▪

The photochemistry of aromatic-N-ylides. Rearrangement and fragmentation patterns

Abstract Rearrangement and fragmentation patterns, which have been observed during uv, irradiation of the following pyridinium ylides, will be discussed: pyridinium methylides, N-iminopyridinium ylides and pyridine-N-oxides. As a rule these mesoionic compounds undergo two competing reactions: i) photolytic cleavage via a triplet state, leading to the corresponding pyridines and to carbenes, nitrenes and oxene respectively; ii) photochemical rearrangement via an excitet singlet state, leading either to ring contraction, to ring enlargement or to ring cleavage. The photochemistry of N-iminopyridinium ylides has been studied in detail, since the photoinduced rearrangement pattern leads in high yield to the isomeric 1, 2-diazepines. Overall quantum yield of this ring enlargement process is low. In order to interpret the uv spectra of these 1-iminopyridinium ylides, their dichroism has been measured using Egger's stretched film technique. Solvent effects and a Pariser-Parr-Pople model point to π-π* transitions for the photoactive band, possibly followed by intramolecular charge transfer.

N-oxides and related compounds. Part 58. Some precursors of pyridinium methylide

1-t-Butoxycarbonylmethylpyridinium ion (3) is pyrolysed to yield successively the 1-carboxymethyl- and the 1-methyl-pyridinium ions. The intermediate ylide (1) could be trapped by benzaldehyde and other electrophiles.1-Carboxymethylpyridinium betaine (5) reacts with aldehydes as the ylide tautomer (6) to give products (8) of aldol reactions, transformations of which are described. The reactions of various other electrophiles with the betaine (5) have been investigated.The ylide (20) from the cation (3) reacts as expected with methyl iodide, benzyl bromide, and benzoyl chloride (at 0 °C). At 25 °C, benzoyl chloride gives a product of further acylation, as do other acid halides.

Studies on ketene and its derivatives. LXXXIII. Reaction of diketene with isoquinolinium and pyridinium methylide derivatives

AbstractReaction of isoquinolinium bis(ethoxycarbonyl)methylide (I) with diketene gave diethyl 1‐acetyl‐2,3‐dihydro‐2‐oxopyrrolo[2,1‐α]isoquinoline‐3,3‐dicarboxylate (VI), which on hydrolysis with dilute hydrochloric acid afforded ethyl 1‐acetyl‐2‐hydroxypyrrolo[2,1‐α]isoquinoline‐3‐carboxylate (IX) and ethyl 3‐methylpyrrolo[2,1‐α]isoquinoline‐3‐carboxylate (X). On the other hand, isoquinolinium cyanoethoxycarbonylmethylide (IIa) reacted with diketene to give isoquinolinium cyano(3‐ethoxycarbonyloxy‐3‐butenoyl)methylide (XIIIa) which was isomerized to isoquinolinium cyano(3‐ethoxycarbonyloxy‐2‐butenoyl)methylide (XIII). Similarly, reactions of isoquinolinium cyanomethoxycarbonylmethylide (IIb) and pyridinium cyanoalkoxycarbonyl‐methylide (IIIa,b) with diketene gave rise to the corresponding cyano(3‐alkoxycarbonyloxy‐3‐butenoyl)methylides (XIIb, XVIa,b).

Addition reactions of heterocyclic compounds. Part LXIV. Indolizines from reactions of hex-3-yne-2,5-dione, but-3-yn-2-one, and allene-carboxylic esters with some nitrogen-containing heterocyclic ylides

Pyridinium methylides combine with hex-3-yne-2,5-dione, but-3-yn-2-one, methyl but-2-ynoate, methyl phenyl-acetylenecarboxylate, dimethyl penta-2,3-dienedioate, and ethyl 2-methylbuta-2,3-dienoate and 2-methylpenta-2,3-dienoate to give indolizines, identified from spectra.

Preparation of Stable 2,3-Dihydroindolizines by the Reactions of Pyridinium Methylides with Various Acrylates

Abstract Pyridinium methoxycarbonylmethylides(5–8), readily obtainable from their corresponding salts(1–4), reacted with various acrylates to afford dimethyl 2,3-trans-dihydroindolizine-1,3-dicarboxylate derivatives(9–20) in moderate yields. These dihydroindolizines were very stable and were not aromatized by heating. However, treatment with lead tetraacetate gave the corresponding indolizine derivatives(21–32) in good yields. The configuration at C-2 and C-3 positions in these dihydroindolizines was assigned to trans from their NMR and by comparison with an authentic specimen(12).

Studies on the Reactions of Heterocyclic Compounds. VI. 1, 3-Dipolar Cycloaddition Reaction of Disubstituted Methylides of Isoquinoline and Pyridine with Acetylenic Compounds

Tetramethyl 3, 10b-dihydropyrrolo [2, 1-α] isoquinoline-1, 2, 3, 3-tetracarboxylate (VI) was isolated for the first time as the primary addition product of a reaction between isoquinolinlium bis (methoxycarbonyl) methylide (V) and dimethyl acetylenedicarboxylate (IV). Treatment of VI with hydrogen chloride and then with potassium carbonate resulted in its isomerization into 2, 3-dihydropyrrolo [2, 1-α] isoquinoline derivative (VII). In the reaction of isoquinolinium dicyanomethylide (XI) with IV, the isomerized 2, 3-dihydro compound (XIII) and the eliminated product (XIV) were produced, instead of their primary adduct (XII). The relation between a substituent group in the 2, 3-dihydrotype compounds and their reactivity was examined. On the other hand, in the reaction of disubstituted pyridinium methylides with acetylenic compounds, only aromatized products were obtained.