a
State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, P. R. of China
c
School of Chemistry and Chemical Engineering, Henan Normal University., Henan, P. R. of China
› InstitutsangabenWe are grateful for financial support from the National Natural Science Foundation of China (Nos. 21672047 and 22101066), the Science and Technology Planning Project of Shenzhen (JCYJ20180306171926120 and JCYJ20210324133001004), the Natural Science Foundation of Guangdong Province (No. 2020A1515010564), and Guangdong Basic and Applied Basic Research Foundation (No. 2021A1515220069). W.X. is grateful to the Talent Plan of the Pearl River in Guangdong, a start-up fund from the Shenzhen Government, and for financial support from Guangdong Province Covid-19 Pandemic Control Research Fund (no. 2020KZDZX1218). The project was also supported by the Open Research Fund of the School of Chemistry and Chemical Engineering, Henan Normal University.
A sustainable, practical, and direct strategy for the reduction of carbonyl compounds, including aldehydes and ketones, by an electrochemical pathway is presented, affording a variety of alcohols or diols as major products with decent yields. The reaction proceeds smoothly in the air at ambient temperatures with DABCO as the sacrificial reductant. Mechanistic studies revealed that direct electrochemical reduction followed by either protonation or radical–radical homocoupling is the main pathway.
18(4-Methylphenyl)(phenyl)methanol (2a)1; Gram-Scale Synthesis
A 100 mL beaker equipped with a magnetic stirrer bar was charged with ketone 1a (1.0 equiv, 6.0 mmol) and electrolyte Bu4NBF4 (0.05 M), followed by DABCO (3.0 equiv, 2.02 g, 18 mmol) and DMF (50 mL). The flask was subsequently equipped with a Pt plate anode (30 × 30 × 0.2 mm3) and a graphite plate cathode (20 × 20 × 3 mm3) separated by ~2 cm. Constant-current electrolysis (10 mA) was then performed at rt under air with vigorous stirring for 50 h. When the reaction was complete (TLC), the mixture was poured into brine and extracted with EtOAc (×3). The combined organic layer was washed with brine (×3) then dried (Na2SO4) and concentrated under reduced pressure. The resulting mixture was purified by column chromatography (silica gel, EtOAc–PE) to give a white solid; yield: 1.08 g (91%).
1H NMR (400 MHz, CDCl3): δ = 7.39 (d, J = 7.0 Hz, 2 H), 7.34 (t, J = 7.5 Hz, 2 H), 7.27 (d, J = 8.0 Hz, 3 H), 7.15 (d, J = 7.9 Hz, 2 H), 5.82 (s, 1 H), 2.34 (s, 3 H), 2.24 (s, 1 H). 13C NMR (101 MHz, CDCl3): δ = 144.0, 141.0, 137.4, 129.3, 128.5, 127.5, 126.6, 126.5, 76.2, 21.2.
19a
Maeda H,
Maki T,
Eguchi K,
Koide T,
Ohmori H.
Tetrahedron Lett. 1994; 35: 4129
