The Paternò-Büchi reaction—Mechanisms and application to organic synthesis

• Published in: Journal of photochemistry and photobiology. C, Photochemistry reviews Vol. 33; pp. 83 - 108
• Main Authors: Fréneau, Maxime, Hoffmann, Norbert
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2017; Elsevier Science Ltd; Elsevier
• Subjects: Carbonyl compounds; Carbonyls; Chemical Sciences; Chemical synthesis; Electron spin; Electron transfer; Organic chemicals; Organic chemistry; Organic synthesis; Oxetanes; Photochemical reactions; Photochemicals; Photochemistry; Photocycloadditions; Reaction mechanism; Reaction mechanisms; Stereoselectivity; Stereoselectivity; Organic synthesis; Reaction mechanism; Oxetanes; Photocycloadditions
• ISSN: 1389-5567; 1873-2739
• DOI: 10.1016/j.jphotochemrev.2017.10.002

[Display omitted] •An overview of the reaction mechanisms is provided and the role of diradical intermediates is highlighted.•The stereoselectivity of the reaction is discussed as a result of the reaction mechanism.•Applications in organic synthesis are reported. The [2+2] photocycloaddition between an electronically excited carbonyl compound and an alkene leading to oxetanes (Paternò-Büchi reaction) is one of the most investigated organic photochemical reaction. Regio-, stereo- and site selectivities are discussed as a consequence of the reaction mechanism. Spin multiplicity and electron transfer have a significant impact on the outcome of the reaction. Typical carbonyl and alkene reaction partners are presented indicating scope and limitation of the reaction. The Paternò-Büchi reaction possesses particular interest for being applied to organic synthesis, considering the difficulty for non-photochemical reactions to obtain oxetanes, with or without stereoselectivity. Mechanistic details are particularly focused. It has been applied as key step in various multi-step syntheses.