Photoreactions of trans-1-o-Hydroxyphenyl-2-phenylcyclopropane

Abstract

The photochemistry of trans-1-o-hydroxyphenyl-2-phenylcyclopropane, trans-1, was studied under a variety of experimental conditions. Direct irradiation through quartz in cyclohexane gave rise mainly to ring-expanded products, 2-phenyl-3,4-dihydro-2H-benzopyran, 2, 2-benzyl-2,3-dihydrobenzofuran, 3, and 1-o-hydroxyphenylindan, 4. The major products, 2 and 3, are rationalized by intramolecular proton transfer. However, a significant fraction of 3 is formed via ring-opening to cinnamylphenol, 5. An additional product, o-(alpha-cyclohexylmethyl)phenol, 7, suggests fragmentation of trans-1 and (formal) insertion of o-hydroxyphenylcarbene into cyclohexane. Direct irradiation in methanol produced methanol adducts 8 and 9 instead of 2, 3, 4, or 7. Finally, acetone-sensitized irradiation of trans-1 resulted in geometric isomerization to cis-1; this result can be rationalized via a biradical intermediate.

Iron‐Catalyzed Oxidative Radical Cross‐Coupling/Cyclization between Phenols and Olefins

“…[7] Moreover, the formation of higher-molecular-weight polymer products or C,O-connected phenol portions, for example quinol ethers, might also occur depending on the oxidant and the experimental conditions. Herein, we present an iron-catalyzed oxidative radical cross-coupling/ cyclization between phenol and olefin towards the synthesis of dihydrobenzofuran [9] at room temperature in a highly selective manner. Herein, we present an iron-catalyzed oxidative radical cross-coupling/ cyclization between phenol and olefin towards the synthesis of dihydrobenzofuran [9] at room temperature in a highly selective manner.…”

Iron‐Catalyzed Oxidative Radical Cross‐Coupling/Cyclization between Phenols and Olefins

“…Herein, we present an iron-catalyzed oxidative radical cross-coupling/ cyclization between phenol and olefin towards the synthesis of dihydrobenzofuran [9] at room temperature in a highly selective manner.…”

Facile Approach to 4-Substituted 2(5H)-Furanones

“…The success of this reaction provides an efficient and convenient approach to 4-substituted 2(5 H )-furanones. For the active alkenyl and cyclopropyl functions could be further elaborated, our reaction procedure might opened a door to prepare many other types of 4-substituted 2(5 H )- furanones. The biological activities of these compounds are being studied.…”