Access to β-Lactams via Iron-Catalyzed Olefin Oxyamidation Enabled by the π-Accepting Phthalocyanine Ligand

Herein, we report the development of an ironcatalyzed olefin oxyamidation by utilizing tethered dioxazolones as the nitrenoid precursor to produce valuable beta-lactam scaffolds. Mechanistic studies revealed that a relatively strong pi-accepting ability of the phthalocyanine ligand is critical in generating the key triplet iron-imidyl radical intermediate to enable the 4-exo-triglactamization with the incorporation of oxygen nucleophiles in high diastereoselectivity. This cyclization approach was readily extended to the highly efficient gamma-lactam synthesis (TON > 300).

Automated summary

In this study, an iron-catalyzed olefin oxyamidation using tethered dioxazolones as nitrenoid precursors was developed to produce valuable beta-lactam scaffolds with high diastereoselectivity. Mechanistic studies showed that the strong pi-accepting ability of the phthalocyanine ligand is critical in generating the key triplet iron-imidyl radical intermediate for efficient cyclization. The approach was also extended to the highly efficient synthesis of gamma-lactams with a TON > 300.