{"title":"Synthesis of 3-arylated chlorophyll-a derivatives via Diels–Alder reaction and their atropisomerism","authors":"Saki Kichishima, Hiroaki Maeda, Hitoshi Tamiaki","doi":"10.1002/poc.4546","DOIUrl":null,"url":null,"abstract":"<p>Methyl pyropheophorbides-<i>a</i> possessing an <i>o</i>/<i>m</i>-(methoxycarbonyl)phenyl group at the 3-position were prepared by Diels–Alder reaction of 3-(<i>trans</i>-1,3-butadienyl)chlorin with methyl propiolate and successive didehydrogenation of the resulting 1,4-cyclohexadienes. The 3-arylated chlorin bearing the sterically demanding <i>o</i>-COOMe group as the major product was a 1:1 mixture of high-performance liquid chromatography-separable rotational isomers around the C3–C3<sup>1</sup> bond, while the minor product with the <i>m</i>-COOMe was less sterically hindered to exhibit rapid atropisomerization at room temperature. The 3-aryl group of the major product was nearly perpendicular to the chlorin π-system and less conjugated with the chlorin moiety than that of the minor product wherein more π-conjugation occurred to give slightly red-shifted Qy bands. Although both the atropisomers of the <i>o</i>-substitute in dichloromethane showed similar visible absorption bands and fluorescence emission data, their circular dichroism bands in the ultraviolet-C light region were dependent on the stereochemistry.</p>","PeriodicalId":16829,"journal":{"name":"Journal of Physical Organic Chemistry","volume":null,"pages":null},"PeriodicalIF":1.9000,"publicationDate":"2023-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Physical Organic Chemistry","FirstCategoryId":"92","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/poc.4546","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, ORGANIC","Score":null,"Total":0}
引用次数: 0
Abstract
Methyl pyropheophorbides-a possessing an o/m-(methoxycarbonyl)phenyl group at the 3-position were prepared by Diels–Alder reaction of 3-(trans-1,3-butadienyl)chlorin with methyl propiolate and successive didehydrogenation of the resulting 1,4-cyclohexadienes. The 3-arylated chlorin bearing the sterically demanding o-COOMe group as the major product was a 1:1 mixture of high-performance liquid chromatography-separable rotational isomers around the C3–C31 bond, while the minor product with the m-COOMe was less sterically hindered to exhibit rapid atropisomerization at room temperature. The 3-aryl group of the major product was nearly perpendicular to the chlorin π-system and less conjugated with the chlorin moiety than that of the minor product wherein more π-conjugation occurred to give slightly red-shifted Qy bands. Although both the atropisomers of the o-substitute in dichloromethane showed similar visible absorption bands and fluorescence emission data, their circular dichroism bands in the ultraviolet-C light region were dependent on the stereochemistry.
期刊介绍:
The Journal of Physical Organic Chemistry is the foremost international journal devoted to the relationship between molecular structure and chemical reactivity in organic systems. It publishes Research Articles, Reviews and Mini Reviews based on research striving to understand the principles governing chemical structures in relation to activity and transformation with physical and mathematical rigor, using results derived from experimental and computational methods. Physical Organic Chemistry is a central and fundamental field with multiple applications in fields such as molecular recognition, supramolecular chemistry, catalysis, photochemistry, biological and material sciences, nanotechnology and surface science.