Cobalt-Hydride-Catalyzed\nAlkene-Carboxylate Transposition\n(ACT) of Allyl Carboxylates

The\nalkene-carboxylate transposition (ACT) of allyl carboxylates\nis one of the most atom-economic and synthetically reliable transformations\nin organic chemistry, as allyl carboxylates are versatile synthetic\nintermediates. Classic ACT transformations, including [3,3]-sigmatropic\nrearrangement and transition metal-catalyzed allylic rearrangement,\ntypically yield 1,2-alkene/1,3-acyloxy shifted products through a\ntwo-electron process. However, position-altered ACT to produce distinct\n1,3-alkene/1,2-acyloxy shifted products remains elusive. Here, we\nreport the first cobalt-hydride-catalyzed ACT of allyl carboxylates,\nenabling access to these unprecedented 1,3-alkene/1,2-acyloxy shifted\nproducts via a 1,2-radical migration (RaM) strategy. This transformation\ndemonstrates broad functional group tolerance, is suitable for late-stage\nmodification of complex molecules, and is amenable to gram-scale synthesis.\nIt also expands the reaction profiles of both allyl carboxylates and\ncobalt catalysis. Preliminary experimental and computational studies\nsuggest a mechanism involving metal-hydride hydrogen atom transfer\n(MHAT) and the 1,2-RaM process. This reaction is expected to serve\nas the basis for the development of versatile Co–H-catalyzed\ntransformations of allyl carboxylates, generating a wide array of\nvaluable building blocks for synthetic, medicinal, and materials chemistry.