2026-04-17T03:09:20Zhttps://recercat.cat/oai/request

oai:recercat.cat:2072/5329292024-12-20T23:07:28Zcom_2072_300912com_2072_4427col_2072_301309

Stereoselective conjugate cyanation of enals by combining photo-redox and organocatalysis Berger, Martin Ma, Dengke Baumgartner, Yann Wong, Thomas Hin-Fung Melchiorre, Paolo Precise control over the selectivity of a reaction is a fundamental target. While great advances have been obtained in achieving stereocontrol, the selective manipulation of functional groups within a substrate (chemoselectivity) is still a challenge. The cyanation of aldehydes offers an illustrative example: the 1,2-addition of nucleophilic cyanide to the aldehydic group was one of the first examples of a stereoselective catalytic process. By contrast, the conjugate cyanation of linear α,β-unsaturated aldehydes has remained elusive, even in a racemic variant. The main difficulty lies in achieving 1,4-chemoselectivity over the preferred cyanide 1,2-addition. Here, we report an asymmetric catalytic method to achieve the exclusive conjugate cyanation of enals. The synergistic action of a chiral organocatalyst with a visible-light-activated photoredox catalyst promotes the single-electron reduction of enals, inducing a formal inversion of polarity. The resulting chiral radical, being nucleophilic in character, is then intercepted by an electrophilic cyanide source with perfect 1,4-chemoselectivity and good stereocontrol. 2023-10-03T06:11:47Z 2024-04-23T11:12:38Z 2023-10-03T06:11:47Z 2024-04-23T11:12:38Z 2023-10-03T06:11:47Z 2024-04-23T11:12:38Z 2023-04-06 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion http://hdl.handle.net/2072/532929 https://doi.org/10.1038/s41929-023-00939-y eng MCIN AEI/10.13039/501100011033 (CEX2019-000925-S) and Agencia Estatal de Investigación (PID2019-106278GB-I00) Austrian Science Fundation (FWF, J4603-N) for an Erwin-Schrödinger postdoctoral fellowship Swiss National Science Foundation (P2BSP2_200098) EU for a Horizon 2020 Marie Skłodowska-Curie Fellowship (H2020-MSCA-IF-2019 894795) Government of Catalonia for an FI Fellowship (2021FI−B00304) info:eu-repo/semantics/openAccess Creative Commons Attribution 4.0 International. CC-BY 4.0 Springer Nature RECERCAT (Dipòsit de la Recerca de Catalunya)