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

A thermal O-to-C [1,3]-rearrangement of alpha-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.

Automated summary

The thermal O-to-C [1,3]-rearrangement of alpha-hydroxy acid derived enol ethers was achieved under mild conditions, facilitated by the 2-aminothiophenol protection of carboxylic acids. Experimental and theoretical evidence was presented for dissociative radical pair formation, captodative stability via aminothiophenol, and a unique solvent effect. Aminothiophenol was deprotected from rearrangement products and after derivatization to useful synthons.