α‐Chlor‐nitrone V: Substitutionsreaktionen an Olefin‐ und Benzolderivaten. Eine Methode zur Darstellung von β,γ‐un‐gesättigten und β‐ arylsubstituierten Aldehyden. Stereospezifische Bildung von tetra‐alkylsubstituierten Olefindoppelbindungen. Über synthetische Methoden, 9. (vorläufige) Mitteilung

Abstract

Abstract The Ag + ‐induced α‐chloro‐aldonitrone/olefin reaction in polar solvents can proceed by substitution, thereby providing a method for the preparation of β, γ‐unsaturated aldehydes. Positional as well as configurational retention of the olefinic double bond are mechanistically significant and preparatively useful characteristics of this process. Substitution also occurs with great ease at nucleophilic aromatic nuclei; this offers a simple preparative route to certain β‐aryl‐aldehydes. The results illustrate a general aspect of the chemistry of α‐chloro‐aldonitrones: the N‐alkenyl‐N‐alkyl‐nitrosonium‐ions derived from them can serve as preparative equivalents of the elusive corresponding α‐acyl‐carbonium‐ions.