Iron‐Catalyzed Aminomethyloxygenative Cyclization of Hydroxy‐α‐diazoesters with N,O‐Aminals

Abstract

Summary of main observation and conclusion A new and efficient cyclization reaction has been developed to synthesize cyclic α,α‐disubstituted β‐amino esters via iron‐catalyzed intramolecular aminomethyloxygenative cyclization of diazo compounds with N,O‐aminal under mild reaction conditions. A broad range of hydroxy‐α‐diazoesters with different substituents and various N,O‐aminals were compatible with this protocol, affording the corresponding α,α‐disubstituted β‐amino esters bearing a five‐ to eight‐membered oxacycle in good yields.

Palladium‐Catalyzed Aminomethylation of Nitrodienes and Dienones via Double C—N Bond Activation

“…On the base of the previous studies [ 13‐14,21‐29 ] and our experimental results, a plausible mechanism for this α‐aminomethylation is proposed (Figure 1). Firstly, the aza‐Michael addition reaction takes place between the aminal 1a and the nitrodiene 2a to form the key intermediate I .…”

Brønsted Acid Catalyzed Cyclization of Aminodiazoesters with Aldehydes to 3-Carboxylate-N-Heterocycles

“…However, as far as we know, only one special example for the synthesis of 3-carboxylate indoles with iminophenyl-diazoacetates as reactants by using this strategy has been reported, in which the aromatization might be the driving force to release the N 2 to furnish the cyclization reaction . In connection with our interest in exploring new reactions with diazo compounds as starting materials, herein, we wish to report a nucleophilic cyclization reaction of aminodiazoesters with aldehydes, leading to the furnishing of a series of 5–7-membered 3-carboxylate- N -heterocycles (Scheme b). The in situ formed iminium ion was adopted as an electrophile to furnish the cyclization and the inherent positive charge imparted a driving force to extrude the N 2 .…”