[1,3]-Claisen Rearrangement via Removable Functional Group Mediated Radical Stabilization

Org Lett. 2021 Feb 5;23(3):890-895. doi: 10.1021/acs.orglett.0c04109. Epub 2021 Jan 14.


A thermal O-to-C [1,3]-rearrangement of α-hydroxy acid derived enol ethers was achieved under mild conditions. The 2-aminothiophenol protection of carboxylic acids facilitates formation of the [1,3] precursor and its thermal rearrangement via stabilization of a radical intermediate. Experimental and theoretical evidence for dissociative radical pair formation, its captodative stability via aminothiophenol, and a unique solvent effect are presented. The aminothiophenol was deprotected from rearrangement products as well as after derivatization to useful synthons.