Paternò–Büchi reaction

Here an electronically excited carbonyl group is added to a ground state olefin yielding an oxetane.

The Paternò–Büchi reaction, named after Emanuele Paternò and George Büchi who established its basic utility and form, is a photochemical reaction that forms four-membered oxetane rings from a carbonyl and an alkene.^{[1] [2] [3]}

With substrates benzaldehyde and 2-methyl-2-butene the reaction product is a mixture of structural isomers:

Another substrate set is benzaldehyde and furan ^[4]

References

1. E. Paterno, G. Chieffi (1909). ".". Gazz. Chim. Ital. 39: 341.
2. G. Büchi, Charles G. Inman, and E. S. Lipinsky (1954). "Light-catalyzed Organic Reactions. I. The Reaction of Carbonyl Compounds with 2-Methyl-2-butene in the Presence of Ultraviolet Light". Journal of the American Chemical Society 76 (17): 4327–4331. doi:10.1021/ja01646a024.
3. Thorsten Bach (1998). "Stereoselective Intermolecular [2 + 2]-Photocycloaddition Reactions and Their Application in Synthesis". Synthesis 1998: 683–703. doi:10.1055/s-1998-2054.
4. Paternò–Büchi Reaction as a Demonstration of Chemical Kinetics and Synthetic Photochemistry Using a Light Emitting Diode Apparatus Matthew P. Thompson, Jonathan Agger, and Lu Shin Wong Journal of Chemical Education 2015 92 (10), 1716-1720 doi:10.1021/acs.jchemed.5b00129