Photocatalytic Cross‐Pinacol Coupling Promoted by Carbon Dioxide

• Published in: Chemistry : a European journal Vol. 29; no. 44; pp. e202300840 - n/a
• Main Authors: Okumura, Shintaro, Takahashi, Teruki, Torii, Kaoru, Uozumi, Yasuhiro
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 04.08.2023; Wiley Subscription Services, Inc
• Subjects: Aldehydes; carbinol anions; Carbon dioxide; Carbonyl compounds; Carbonyls; Chemistry; Chemistry, Multidisciplinary; Coupling (molecular); Cross coupling; cross-pinacol coupling; Dimerization; Diols; Electron transfer; Ketones; photocatalysis; Physical Sciences; Science & Technology; Substrates; umpolung; carbon dioxide; umpolung; COMPLEXES; ALDEHYDES; POTENTIALS; MOLECULES; ATOM; KETONES; cross-pinacol coupling; carbinol anions; ELECTRODE; CARBOXYLATION; photocatalysis
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202300840

Cross‐pinacol coupling of two different carbonyl compounds was achieved through successive one‐electron transfer processes under photocatalytic conditions. In the reaction, an umpoled anionic carbinol synthon was generated in situ to react nucleophilically with a second electrophilic carbonyl compound. It was revealed that a CO2 additive promoted the photocatalytic generation of the carbinol synthon to suppress undesired radical dimerization. A wide variety of aromatic and aliphatic carbonyl substrates underwent the cross‐pinacol coupling to afford the corresponding unsymmetric vicinal 1,2‐diols, in which even a combination of carbonyl reactants with similar structures such as two aldehydes and two ketones were also well tolerated with high cross‐coupling selectivity. A first photocatalytic cross‐pinacol coupling was achieved. The reaction proceeded with a various combination of two aldehydes, two ketones, or an aldehyde and a ketone to afford the corresponding unsymmetric vicinal 1,2‐diols in up to 91 % yield. In this process, an umpoled anionic carbinol synthon was generated in situ, by the assistance of CO2 additive, to react nucleophilically with a second electrophilic carbonyl compound.Photocatalytic Cross‐Pinacol Coupling Promoted by Carbon Dioxide (S. Okumura, Y. Uozumi et al.)