Catalytic asymmetric total syntheses of myrtucommuacetalone, myrtucommuacetalone B, and callistrilones A, C, D and E

Abstract

A highly concise catalytic approach for the first asymmetric total syntheses of myrtucommuacetalones and callistrilones is reported.

Antiviral Triketone‐Phloroglucinol‐Monoterpene Adducts from Callistemon rigidus

“…Callistemon rigidus , an evergreen shrub of the Myrtaceae family that cultivated in Guangdong and Guangxi provinces of China, had been used as a folk medicine for treating cough and bronchitis . Our previous studies on this plant had led to the isolation of several bioactive phloroglucinol derivatives . During our further investigation of the phloroglucinol constituents from this plant, six new phloroglucinol derivatives callistrilones F – K ( 1 – 6 ) with rare triketone‐phloroglucinol‐monoterpene skeletons were obtained ( Figure ).…”

Antibacterial Triketone‐Phloroglucinol‐Triketone Adducts fromMyrtus communis

“…Discovery of new antibacterial lead compounds is desperately required [1,2] . Phloroglucinol derivatives from Myrtaceae plants possess diverse backbones and biological effects including antibacterial activity [3–8] . The plant Myrtus communis (Myrtaceae) is an evergreen shrub mainly grown in the Mediterranean area, which can be used to treat hypoglycemia, disinfection and antisepsis in traditional medicine [9,10] .…”

“…The plant Myrtus communis (Myrtaceae) is an evergreen shrub mainly grown in the Mediterranean area, which can be used to treat hypoglycemia, disinfection and antisepsis in traditional medicine [9,10] . Previous investigations has resulted in the identification of some phloroglucinol derivatives with antibacterial activities from this plant [4,11–13] . Over the course of our ongoing effort to obtain bioactive and structure unique constituents from Myrtaceae plants, [14–19] three pairs of new triketone‐phloroglucinol‐triketone adducts with an rare polycyclic ketal skeleton, myrtucyclitones A–C ((+)‐ and (−)‐ 1 – 3 ), ( Figure 1) were obtained from the title plant.…”

Cajuputones A–C, β‐Triketone Flavanone Hybrids from the Branches and Leaves of Melaleuca cajuputi

“…[6 -9] Recent years, the discovering of diverse β-triketone-terpene hybrids form Myrtaceae family has made Melaleuca genus be a hot spot in natural products research field. [10][11][12][13] Melaleuca cajuputi (previous name: Melaleuca leucadendron) was a widely cultivated landscape plant in southern China and was native to Australia (tea tree). The leaves and barks of M. cajuputi are used as a traditional Chinese medicine to treat inflammatory wounds and rheumatic arthralgia.…”

“…Besides many monoterpene constituents found in the essential oil, [3–5] phytochemical investigations of Melaleuca species have also revealed many nonvolatile secondary metabolites, including β ‐triketone, flavonoids, triterpenoids, and tannins [6–9] . Recent years, the discovering of diverse β ‐triketone‐terpene hybrids form Myrtaceae family has made Melaleuca genus be a hot spot in natural products research field [10–13] …”