C_sp3–H Imination Using Arylazo Sulfone as a N Source: An Approach to Access Imines

Abstract

An unprecedented Csp3–H imination reaction using arylazo sulfones as the readily accessible and stable N source is reported. The synthetic virtues are demonstrated through mild conditions, simple operation, good air compatibility, and functional group tolerance, as well as suitability for gram-scale reaction. The resulting imines can be further converted to α-amino acids. The presented results shed light on an unusual usage of arylazo sulfones and will inspire novel experimental design by using arylazo sulfones as the N source.

Arylazo sulfones: multifaceted photochemical reagents and beyond

“…Hence, the authors were successful in developing a new application of the reagent as a readily accessible and stable nitrogen source for the Csp 3 –H imination reaction. 73…”

Mild diazenylation of Csp2–H and Csp3–H bonds via arylazo sulfones

“…Based on this, we have also discovered that the attack of a carboanion on an aryl-substituted N atom, which is more receptive to nucleophilic addition, results in a novel imination reaction. 13 However, if the Ms-substituted N atom, which is relatively weakly electrophilic, can accept a nucleophilic attack, it will open up the use of arylazo sulfone as the diazo source (Scheme 1C). The unexplored potential of arylazo sulfones as electrophilic diazo sources makes us curious about their applicability in the synthesis of non-symmetric azo compounds, which would also improve the atom utilization efficiency and E-factor 14 (compared to arylazo sulfones as aryl radical precursors).…”