Paterno-Büchi reaction

Equipment

• LUMOS 43
• Quartz NMR tube

Chemicals

• Benzaldehyde: 10 mg
• Furane: 1 mL

Procedure

Benzaldehyde 1 (10 mg) is dissolved in 1 mL of furan 2 in a standard quartz NMR tube. The sample is then irradiated in a LUMOS 43 reactor at 375nm for 16 hours. Evaporation of the excess furan gives a mixture of unreacted benzaldehyde 1 and the [2+2] cycloadduct 3. With neither stirring, nor degassing and by using technical grade reagent without additional purification, a yield of 54% is obtained. The product is easily identifiable by ¹H-NMR from the crude mixture, taking the unreacted benzaldehyde singlet (d10.03 ppm) as an internal standard: 3.67 (m, 1H), 5.48 (t, J=3 Hz, 1H), 5.58 (d, J=3 Hz, 1H), 6.57 (d, J=4.5 Hz), 6.73 (d, J=3 Hz, 1H), 7.5 (5H).

Reference

A.G. Griesbeck, S. Stadtmüller, Chem. Ber. 1990, 123, 357-362.