α-Chiral Amines via Thermally Promoted Deaminative Addition of Alkylpyridinium Salts to Sulfinimines

Abstract

A deaminative reaction of Katritzky alkylpyridinium salts and sulfinimines has been developed to deliver enantiopure α-chiral amines. The success of this method relied on the discovery of a thermally promoted deamination via single-electron transfer of an anion−π complex of the alkylpyridinium cation with potassium carbonate. This method boasts excellent diastereoselectivity over the α-stereocenter as well as broad functional group and heterocycle tolerance.

Electron donor–acceptor complex-catalyzed photoredox reactions mediated by DIPEA and inorganic carbonates

“…The bulkiness of DIPEA may suppress a competing deprotonating decomposition of complex C , and result in a better regeneration process than with other amines. Although reactions driven by carbonate ion-containing EDA complexes are known, 20 our results indicated that the pair of DIPEA and inorganic carbonates provides a highly efficient EDA donor catalysis system.…”

“…Therefore, an SET from CO 3 2− to the NHPI ester would take place after photon absorption. 20 Considering the standard potentials of DIPEA ( E ox 1/2 = +0.94 V vs. SCE) 21 and a carbonate radical anion (CO 3 ˙ − , E red 1/2 = +1.57 V vs. NHE), 22 a second SET from DIPEA to CO 3 ˙ − would follow spontaneously, generating a DIPEA radical cation. Therefore, the photo-induced SET within the complex is likely a two-step event, and CO 3 2− acts as an “electron shuttle” in the overall SET from DIPEA to the NHPI ester.…”

Light-Induced Activation of C–X Bond via Carbonate-Assisted Anion−π Interactions: Applications to C–P and C–B Bond Formation

“…However, the fact that these donor molecules served as the coupling partners themselves restricts the use of this chemistry for alternate functionalizations of the C–X bond (Scheme b) . Notably, Watson and co-workers have also utilized K 2 CO 3 for the deaminative reaction of sulfimines and Katritzky alkylpyridinium salts via the thermally promoted SET (Scheme c) . Although fascinating, these reactions typically necessitate the prefunctionalization of feedstock molecules that limits the scope of these approaches for any other required transformation.…”

Mary P. Watson Selected to Receive the 2023 ACS Catalysis Lectureship for the Advancement of Catalytic Science

“…The Watson reaction can be used to convert primary amines into a range of derivatives from aryl groups to a simple methyl substituent, which is a challenging transformation . Her method allows common primary amines to be employed in a variety of complex couplings via deaminative acylations, cyanations and reactions with sulfinamines that install stereochemistry. − …”