Palladium/Acid Relay Catalyzed Tandem Heck Coupling/6‐Endo Cyclization between ortho‐Halogenated Benzoates and Unactivated Terminal Alkenes for the Synthesis of 1‐Isochromanones
We report a unique and expeditiousroute to synthesize 1‐isochromanone derivatives through palladium catalyzed tandem Heck coupling/6‐endo hydroacyloxylation cyclization between readily available ortho‐halogenated benzoates and unactivated alkenes. Various 2‐bromo or 2‐iodo benzoates can be coupled efficiently with a broad range of alkenes to afford functionalized 1‐isochromanones in high yields. Significantly
The Preparation of Substituted 3,4-Dihydro-1H-2-benzopyran-1-ones from the Dianions of<i>Ortho</i>-Toluic Acids
作者:Karen C. Hildebran、Tracy L. Cordray、Kam W. Chan、Charles F. Beam
DOI:10.1080/00397919408011300
日期:1994.3
Abstract The dianions of ortho-toluic and α-phenyl-ortho-toluic acids were prepared with lithium diisopropylamide (LDA), condensed with certain aldehydes or ketones, and the resulting intermediates were acid-cyclized to substituted 3,4-dihydro-1H-2-benzopyran-1-ones (dihydroisocoumarins).
A visible-light RuII photoredox Meerwein synthesis of isochromanones and isochromenones is described starting from diazonium salts of differently substituted anthranilic acids and various alkenes. This approach has allowed the reliable and efficient preparation of structures found in many biologically active molecules or used in materials chemistry.
Metal‐ and Oxidant‐Free Electrosynthesis of Heterocycles from 1,2‐Diarylalkene Derivatives
作者:Eunsoo Yu、Hyungguk Kim、Cheol‐Min Park
DOI:10.1002/adsc.202200847
日期:2022.12.8
Synthesis of heterocycles from 1,2-diarylalkene derivatives through electrosynthesis under metal- and oxidant-free conditions has been discovered. Cathodic reduction of 2-alkenylbenzoic acid or anodic oxidation of 2-alkenylbenzamide, 2-alkenylphenol and 2-alkenylaniline leads to the formation of reactive radical intermediates which afford corresponding phthalide, isochroman-1-one, isoindolin-1-one