Highly Robust Iron Catalyst System for Intramolecular C(sp3 )-H Amidation Leading to γ-Lactams

Jeonguk Kweon; Sukbok Chang

doi:10.1002/anie.202013499

Highly Robust Iron Catalyst System for Intramolecular C(sp³ )-H Amidation Leading to γ-Lactams

Angew Chem Int Ed Engl. 2021 Feb 8;60(6):2909-2914. doi: 10.1002/anie.202013499. Epub 2020 Dec 9.

Authors

Jeonguk Kweon^{1

2}, Sukbok Chang^{1

2}

Affiliations

¹ Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
² Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea.

PMID: 33111492
DOI: 10.1002/anie.202013499

Abstract

Disclosed here is the use of an iron catalyst system for an intramolecular C-H amidation toward γ-lactam synthesis from dioxazolone precursors. (Phthalocyanine)Fe^III Cl was found to catalyze this cyclization with extremely high turnover numbers of up to 47 000 under mild and aerobic conditions. On the basis of experimental and computational mechanistic studies, the reaction is suggested to proceed by a stepwise radical pathway involving fast hydrogen atom abstraction followed by radical rebound. A plausible origin for the high turnover numbers along with air-compatibility is also rationalized.

Keywords: iron; lactams; nitrenoid; radicals; reaction mechanisms.

Publication types

Research Support, Non-U.S. Gov't