In contrast to the very large number of special methods applicable to syntheses in the heterocyclic series, relatively few general methods are available. The 1,3-dipolar addition offers a remarkably wide range of utility in the synthesis of five-membered heterocycles. Here the “1,3-dipole”, which can only be represented by zwitterionic octet resonance structures, combines in a cycloaddition with a multiple bond system – the “dipolarophile” – to form an uncharged five-membered ring. Although numerous individual examples of this reaction were known, some even back in the nineteenth century, fruitful development of this synthetic principle has been achieved only in recent years.

1,3-Dipolar Cycloadditions. Past and Future†

Asymmetric 1,3-Dipolar Cycloaddition Reactions

Einer sehr grosen Zahl spezieller Synthesewege in die heterocyclische in die Reihe steht ein nur bescheidener Satz an Aufbaumethoden von allgemeiner Verwendbarkeit gegenuber. Eine erstaunliche Anwendungsbreite bei der Synthese funfgliedriger Heterocyclen kommt der 1.3-Dipolaren Addition zu. Dabei vereinigt sich der nur mit zwitterionischen Oktett-Grenzformeln wiederzugebende „1.3-Dipol” mit einem Mehrfachbindungssystem, dem „Dipolarophil”, in einer Cycloaddition zum ladungsfreien funfgliedrigen Ring. Wenngleich die Kenntnis zahlreicher Einzelbeispiele bis ins vorige Jahrhundert zuruckreicht, gelangte das Syntheseprinzip erst in den letzten Jahren zu fruchtbarer Entfaltung.

1.3‐Dipolare Cycloadditionen Rückschau und Ausblick

The chemistry of side reactions and byproduct formation in the system NMMO/cellulose (Lyocell process)

Intramolecular 1,3-dipolar cycloaddition reactions in targeted syntheses

The Addition of Nitrones to Olefins. Fused Bicyclic Isoxazolidines

The addition of nitrones to olefins. a new route to isoxazolidines

Nuclear Magnetic Resonance Studies of 5,6-Dihalo-2-norbornenes and 2,3-Dihalonorbornanes

Amine Oxides. VII. The Thermal Decomposition of the N-Oxides of N-Methylazacycloalkanes1,2

Conformational Analysis. XI. The Conformers of 2-Chlorocyclohexanone1,3

Norman A. LeBel

Papers

The Addition of Nitrones to Olefins. Fused Bicyclic Isoxazolidines

The addition of nitrones to olefins. a new route to isoxazolidines

Nuclear Magnetic Resonance Studies of 5,6-Dihalo-2-norbornenes and 2,3-Dihalonorbornanes

Amine Oxides. VII. The Thermal Decomposition of the N-Oxides of N-Methylazacycloalkanes1,2

Conformational Analysis. XI. The Conformers of 2-Chlorocyclohexanone1,3