Photochemische Reaktionen I. Über die Photosynthese des Askaridols und verwandter Endoperoxyde

Abstract

und W. P r e s t i n g weiter gesicherte Formel des 1,4-Peroxidop-menthem-( 2) (11).Als bisher einziges in der Natur vorgefundenes stabiles organisc hes Peroxyd nimmt es eine interessante Sonderstellung unter den heute hekannten Naturstoffen ein. Aber auch unter den organischen P eroxyden blieb das Askaridol als Endoperoxyd uber 20 Jahre ohne

Singlet oxygen addition to cyclo-1,3-hexadienes from natural sources and from organocatalytic enal dimerization

“…4 This compound was used as an anthelmintic drug and was among the first targets for the Schenck investigations on photooxygenations using sunlight irradiation of dye solutions which were very early examples of sustainable photocatalysis in synthesis. 5 Our interest in this field of photochemistry arose from the search for new and effective antimalarial peroxides, an intensively investigated area in medicinal chemistry. 6 The natural sesquiterpene artemisinin (qinhaosu), used for centuries in Chinese folk medicine as a plant extract, has initiated and stimulated this field of research.…”

A Boron‐Based Synthesis of the Natural Product (+)‐trans‐Dihydrolycoricidine

“…The [4+2] singlet-oxygen cycloaddition with this substrate has been the subject of numerous studies and is notoriously nonselective. [15] However, diene diboration occurs with excellent regio-and diastereoselectivity, cleanly delivering the 1,4-dihydroxylation product in excellent yield. The outcome with this substrate suggests that substituents on the diene do not necessarily interfere with the reaction and can provide products with enhanced substitution.…”

“…The [4+2] singlet-oxygen cycloaddition with this substrate has been the subject of numerous studies and is notoriously nonselective. [15] However, diene diboration occurs with excellent regio-and diastereoselectivity, cleanly delivering the 1,4-dihydroxylation product in excellent yield.…”

Wirklich grüne Synthese von Artemisinin aus Pflanzenextrakt

“…[18][19][20][21][22] Although plentiful in nature, chlorophyll has rarely been used for synthetic transformations. [23,24] A crude mixture of artemisinin, DHAA, as well as chlorophyll derivatives extracted from A. annua leaves (Table S1 in SI). Extraction for 10 min at 50 °C is best to obtain both reagent and catalyst.…”