The Newman–Kwart rearrangement is a type of rearrangement reaction in which the aryl group of an O-aryl thiocarbamate, ArOC(=S)NMe2, migrates from the oxygen atom to the sulfur atom, forming an S-aryl thiocarbamate, ArSC(=O)NMe2.
[1][2][3] The reaction is named after its discoverers, Melvin Spencer Newman[4] and Harold Kwart.
[7] A Pd-catalyzed process[2] and conditions under photoredox catalysis[8] (both proceeding through complex multistep mechanisms) are known.
These catalytic processes allow for much milder reaction conditions to be used (100 °C for Pd catalysis, ambient temperature for photoredox).
A phenol (1) is deprotonated with a base followed by treatment with a thiocarbamoyl chloride (2) to form an O-aryl thiocarbamate (3).