Versuche an einer neuen Caprolactamsynthese. II [1]. Umlagerung von 3,3‐Pentamethylen‐oxaziridin in Caprolactam

Abstract

3,3‐Pentamethylen‐oxaziridin 1 läβt sich durch Flash‐Pyrolyse bei 300 °C in Caprolactam umlagern. In Gegenwart katalytischer Mengen von Vanadinverbindungen läuft die Umlagerung bereits in siedendem Benzol oder Toluol mit Ausbeuten bis zu 95% ab. Es wird ein homolytischer Mechanismus diskutiert und durch radikalische Alkylierung von Acetylacetonaten wahrscheinlich gemacht.

Free-Radical Rearrangements

“…The conversion 311 -> 312 shown above may equally well involve β scission of the cycloalkylamino radical 315 (546). Instances of similar rearrangements are known.…”

Oxidation of Primary Amines to Oximes with Molecular Oxygen using 1,1-Diphenyl-2-picrylhydrazyl and WO3/Al2O3 as Catalysts

“…Furthermore, neither the amination product of 17 with the starting amine nor amides derived from rearrangement of 17 could be detected among the products. Oxazirane 17 is a very active amination reagent and also undergoes rearrangement to amides …”

Metalloporphyrin-catalysed rearrangement of oxaziridines: an efficient and regioselective synthesis of lactams using ring-enlargement of N-phenyl-spirooxaziridines

“…The photochemical rearrangement is a valuable alternative to Schmidt and Beckmann rearrangements which usually require strongly acidic conditions, causing serious problems such as low regioselectivity of the reactions or decomposition of products.5 The corresponding thermal rearrangement of spirooxaziridines is, however, substrate-dependent and inferior to the photochemical process with respect to the efficiency and selectivity.3 Only one catalyst has been developed for the synthesis of a lactam from a spirooxaziridine. 6 We have recently reported that high valent metalloporphyrins work as a mild and characteristic Lewis-acid catalyst for the rearrangement of oxaziridines into amides.7 Therefore, we expected these metalloporphyrins could be used in the ring-expanding rearrangement of spirooxaziridines into lactams. Reported herein is a new and highly efficient transformation of Narylspirooxaziridines 1 into lactams 2 with high valent metalloporphyrins, especially manganese(ri1) tetraphenylporphyrin, Mn(tpp)Cl.…”