Silyl enol ethers in Paternò-Büchi reactions. Functional group tolerance and the effect of β-alkyl substitution

Photochemical [2 + 2] cycloaddition reaction of carbonyl compounds with Danishefsky diene

Danishefsky diene, trans-1-methoxy-3-trimethylsilyloxy-buta-1,3-diene, has been utilized in organic synthesis in thermal reactions for a long time. The purpose of this study is to investigate the photochemical reaction of ketones with Danishefsky diene. The [2 + 2] photocycloaddition products, oxetanes, were obtained in 65%-99% yield, along with the E to Z photochemical isomerisation of the diene. A mechanism involving intermediary triplet diradicals was proposed to rationalise the formation of the oxetanes.

The Paternò–Büchi reaction – a comprehensive review

This review represents the most complete description of the scientific results obtained on a photochemical reaction described 110 years ago by an Italian scientist.

Oxetane synthesis through the Paternò-Büchi reaction

The Paternò-Büchi reaction is a photochemical reaction between a carbonyl compound and an alkene to give the corresponding oxetane. In this review the mechanism of the reaction is discussed. On this basis the described use in the reaction with electron rich alkenes (enolethers, enol esters, enol silyl ethers, enanines, heterocyclic compounds has been reported. The stereochemical behavior of the reaction is particularly stressed. We pointed out the reported applications of this reaction to the synthesis of naturally occuring compounds.