The Interaction of Carbenes and Nitrenes with Azo-compounds

Abstract

A critical analysis of the literature on the interaction of carbenes and nitrenes with azo-compounds is presented, attention being concentrated on the reactions of aminonitrenes. The bibliography includes 83 references. CONTENTS

Oxidation ofN-Aminophthalimide in the Presence of Conjugated Azoalkenes: Azimines, Azoaziridines, and [1,2,3]Triazoles

“…[11] This process competes with the oxidative addition of N-aminophthalimide (1) to olefins or azo compounds. [2,6,11] Thus, the yield of phthalimide (4) obtained in the course of the oxidation of N-aminophthalimide 1 in the presence of a substrate may be considered an approximate measure of the substrate's reluctance to react with N-acetoxyaminophthalimide A or N-phthalimidonitrene B. However, this does not apply when phthalimide (4) is the complementary product originating from the reaction with the substrate (vide infra).…”

“…Several examples of (ZZ)-, (ZE)-and (EZ)-azimines have been reported in the literature as crystalline and isolable compounds, stable at room temperature in the solid state, but slowly equilibrating in solution. [2,6] The unsymmetrical azo compound 11 can give rise to the formation of two azimine regioisomers. Since one NϪN bond of the resultant azimine is embedded in the heterocyclic ring (with an implicit (E) configuration of the endocyclic azimine moiety) each of the two conceivable azimine regioisomers is anticipated to form two stereoisomers (with E-and Z-configurations of the exocyclic azimine NϪN bond).…”

“…However, heating a solution of (Z)-12 in 1,2-dichlorobenzene or chloroform (in a sealed tube) at 150°C for 65 h converted the azimine (Z)-12 into the corresponding phthalazinedione derivative 14 (Scheme 5). This type of transformation with concomitant extrusion of dinitrogen is a typical reaction of phthalimidoazimines; [2,6] phthalimide (4) and 2-(2,3-dihydro-1,3-dioxo-1H-isoindol-2-yl)-1H-isoindole-1,3(2H)-dione (15) [21] were also formed.…”

“…[2Ϫ5] Furthermore, the oxidative addition of N-aminophthalimide (1) to diazenes (azo compounds) has been reported to provide the phthalimidoazimines D as isolable 1,3-dipolar species. [2,6] amino]phthalimide (8d). The cyclic azoalkene 3,3,5-trimethyl-3H-pyrazole (11) gave a mixture of (Z)-3,3,5-trimethyl- Regardless of the actual intermediate involved in the course of the oxidation of N-aminophthalimide (1) and in the subsequent reaction with olefins or diazenes, it seemed interesting to explore the chemoselectivity of this reaction with substrates containing both types of π-bond functionalities.…”

Oxidative Addition of N-Aminophthalimide to Conjugated and Nonconjugated Alkylazoalkanes

“…No wonder that the reaction follows the rules which we have established for the series of (E)-azoalkanes [7,11]: The reaction proceeds stereospecifically, with retention of azo group configuration, and regioselectively, affording predominantly adducts containing the smaller substituent at the central nitrogen of the azoimine system. No wonder that the reaction follows the rules which we have established for the series of (E)-azoalkanes [7,11]: The reaction proceeds stereospecifically, with retention of azo group configuration, and regioselectively, affording predominantly adducts containing the smaller substituent at the central nitrogen of the azoimine system.…”