Isoquinolinium Methylides Research Articles

Lewis-Acid-Catalyzed Dearomative [4π + 2σ] Cycloaddition of Bicyclobutanes with Isoquinolinium Methylides for the Synthesis of Ring-Fused Azabicyclo[3.1.1]heptanes.

Dearomative cycloadditions are valuable for efficiently generating three-dimensional molecular complexity. However, despite recent reports of cycloadditions of bicyclobutanes (BCBs) for the synthesis of aza-bicyclo[3.1.1]heptanes (aza-BCHeps), which are bioisosteres of meta-substituted aza-arenes, dearomative cycloaddition of BCBs with N-heteroarenes for the synthesis of ring-fused aza-BCHeps has yet to be achieved. Herein, we disclose a method for Lewis acid-catalyzed [4π + 2σ] cycloaddition of isoquinolinium methylides with BCBs, which furnished a diverse array of previously inaccessible ring-fused 3-aza-BCHeps. We demonstrated the synthetic utility of the method by carrying out scaled-up reactions and transforming the products.

Highly Enantioselective Synthesis of [1,2,4]Triazino[5,4-a]isoquinoline Derivatives via (3 + 3) Cycloaddition Reactions of Diazo Compounds and Isoquinolinium Methylides.

An array of chiral [1,2,4]triazino[5,4-a]isoquinoline derivatives were obtained in excellent yields (up to 98%) and with excellent enantioselectivities (up to 99% ee) via a new highly asymmetric (3 + 3) cycloaddition reaction of diazo compounds and isoquinolinium methylides, with a bifunctional chiral phase-transfer catalyst (PTC). Density functional theory calculations show that PTC has a bridge role in the deprotonation/protonation process. The obtained products were transformed into densely functionalized polycyclic heterocompounds with multiple stereocenters.

Unprecedented access to functionalized pyrrolo[2,1-a]isoquinolines from the domino reaction of isoquinolinium ylides and electrophilic benzannulated heterocycles.

We have come across an unexpected reaction between electrophilic indoles and isoquinolinium methylides for accessing functionalized pyrrolo[2,1-a]isoquinolines. The reaction was found in general to yield the products in good yields. We also observed the formation of S-S-bridged bis-pyrrolo[2,1-a]isoquinolines from the reaction of 3-nitro benzothiophene and isoquinolinium methylides.

Catalytic Asymmetric Inverse-Electron Demand 1,3-Dipolar Cycloaddition of Isoquinolinium Methylides with Enecarbamates by a Chiral N,N′-Dioxide/Ag(I) Complex

The first catalytic asymmetric inverse-electron demand [3 + 2]-cycloaddition of isoquinolinium methylides with enecarbamates has been realized by using a N,N′-dioxide/Ag(I) complex. The optically active pyrroloisoquinolines and pyrrolophthalazine were obtained in up to 99% yield, >19:1 d.r., and 95% ee. On the basis of fluorescence, ESI-MS analysis, and X-ray structure of the product, a reasonable transition state was proposed.

ChemInform Abstract: Phosphine‐Catalyzed Dearomatizing [3 + 2] Annulations of Isoquinolinium Methylides with Allenes.

AbstractThe title reaction furnishes highly functionalized pyrroloisoquinolines with high regioselectivity and in moderate to good yields.

Phosphine-catalyzed dearomatizing [3+2] annulations of isoquinolinium methylides with allenes.

A phosphine-catalyzed dearomatizing [3+2] annulation of isoquinolinium methylides with allenoates or allenones yields highly functionalized pyrroloisoquinolines with high regioselectivity and in viable yields.

ChemInform Abstract: Tandem 1,3‐Dipolar Cycloadditions of Pyridinium or Isoquinolinium Methylides with Olefinic Dipolarophiles Leading to Cycl(3.2.2)azines. “Enamine Route” as a New Generation Method of Azomethine Ylides.

AbstractCycloaddition reaction of the pyridinium methylides, generated in situ from (I), with the maleimides (II) yields the monocycloadducts (III) which undergo a second cyclization reaction with the olefines (II) or (V) to form the biscycloadducts (IV) or (VI).

Tandem 1,3-dipolar cycloadditions of pyridinium or isoquinolinium methylides with olefinic dipolarophiles leading to cycl[3.2.2]azines. Enamine route as a new generation method of azomethine ylides

Tandem 1,3-dipolar cycloadditions of pyridinium or isoquinolinium methylides with olefinic dipolarophiles leading to cycl[3.2.2]azines. Enamine route as a new generation method of azomethine ylides

ChemInform Abstract: Cycloaddition Reactions of Highly Stabilized Isoquinolinium Methylides to Nonactivated Olefins and Electron‐Rich Olefins.

AbstractThe novel cycloaddition reaction of ylides (I) with aryl‐substituted olefins (e.g.

Cycloaddition Reactions of Highly Stabilized Isoquinolinium Methylides to Nonactivated Olefins and Electron-Rich Olefins

Abstract Highly stabilized isoquinolinium methylides bearing two electron-withdrawing substituents at the ylide carbon undergo cycloadditions with aryl-substituted olefins (acenaphthylene, (E)- and (Z)-stilbenes, indene, and styrene), alkyl-substituted olefins (norbornene, (Z)-3-hexene-1,6-dinitrile, 1-hexene, 2-propen-1-ol, and 3-(trimethylsilyloxy)propene), and electron-rich olefins (vinylene carbonate, butyl vinyl ether, and phenyl vinyl sulfide). These cycloadditions proceed in an exclusively regioselective and mostly stereoselective manner.

ChemInform Abstract: Stereoselective Cycloadditions of Pyridinium or Isoquinolinium Methylides with Olefinic Dipolarophiles and Subsequent Cycloadditions of the Cycloadducts with Nitrile Oxides.

AbstractThe ylide (II), generated in situ by treatment of (I) with Et3N, reacts with olefins (III) or (VII) to give labile adducts of type (V).

Stereoselective Cycloadditions of Pyridinium or Isoquinolinium Methylides with Olefinic Dipolarophiles and Subsequent Cycloadditions of the Cycloadducts with Nitrile Oxides

Abstract Pyridinium or isoquinolinium methylides undergo highly stereo- and regioselective cycloadditions with olefinic dipolarophiles to form unstable tetrahydroindolizine derivatives. One of the two double bonds existing in the dihydro heteroaromatic ring of the cycloadducts reacts with nitrile oxides, in the same flask, in stereo-, regio-, and periselective fashions to lead to stable isoxazole-fused tetrahydroindolizines in good yields.

Synthesis of Benzo[g]indolizines. Reaction of Acid Anhydrides with Isoquinolinium Methylides

Synthesis of Benzo[g]indolizines. Reaction of Acid Anhydrides with Isoquinolinium Methylides

Reaction of isoquinolinium methylides with ketones (author's transl)

Reaction of isoquinolinium methylides with ketones (author's transl)

Studies on Ketene and Its Derivatives (XCIII). Reaction of Ketene with Isoquinolinium Methylides

Studies on Ketene and Its Derivatives (XCIII). Reaction of Ketene with Isoquinolinium Methylides

Réactivité des ylures d'isoquinoléinium: Etude par ESCA de la réaction d'echange de substituant

The reactivity of isoquinolinium methylides has been studied by ESCA and CNDO/2 calculations of charge density distribution, the negative charge of the ylide carbon is mainly delocalized on electron withdrawing substituents. This fact suggests a novel reaction mechanism involving a 1,2-cycloaddition to a ketene intermediate, a mechanism already invoked to explain pyridinium ylide addition reactions to acetylenic derivatives.