Brominated polyunsaturated lipids and their stereochemistry from the Chinese marine sponge Xestospongia testudinaria

Gold-catalyzed stereoselective cycloisomerization of allenoic acids for two types of common natural γ-butyrolactones

“…Xestospongienes are a series of brominated polyunsaturated lipids isolated from the Chinese marine sponge Xestospongia testudinaria (shown in Fig. 1a ) 4 . No total synthesis has been reported yet.…”

“…The reaction of ( R )- 1c , 2k , and ( S )-diphenylprolinol ( S )- 3a in a ratio of 1:1.5:1.5 afforded ( R a , R )- 4ck as a single stereoisomer in 47% yield with >99% ee and >99:1 d.r. Hydrolysis of ( R a , R )- 4ck was conducted subsequently by its treatment with LiOH∙H 2 O at 90 °C for 1.5 h affording ( R a , R )- 5k , which was cycloisomerized with 10 mol% of AuCl(LB-Phos) at −30 °C to afford (5 S ,1′ E ,3′ R )- 6k , i.e., xestospongiene F (reported as xestospongiene E 4 ) in 94% yield with >99% ee and >99:1 d.r (Fig. 6c ).…”

“…Natural products are a big treasure for human beings, which exhibit rich academic and industrial potentials due to their structural diversity and biological activities. As we know, γ-butyrolactones with common structures of γ-( E )-vinylic and alkylic γ-butyrolactones, E- I 1 – 4 and II 5 – 10 , exist extensively in nature and many of them have been identified with interesting biological potentials, such as anti-HIV 1 , anti-fungal 2 , 9 , cytotoxic 3 , anti-bacterial 7 , anti-proliferative 8 activities, etc., featuring applications in pharmacy (Fig. 1 ).…”

Xestospongienols A–L, Brominated Acetylenic Acids from the Chinese Marine Sponge Xestospongia testudinaria

“…The sponge Xestospongia testudinaria (Nepheliospongiidae) is reported to generate diverse brominated fatty acids [8], and it is a main species inhabiting in Hainan Island (South China Sea). Our previous investigation resulted in the isolation and characterization of 39 brominated polyunsaturated compounds from Chinese X. testudinaria [9]. In this article, we report the isolation and structural elucidation of additional twelve new brominated acetylenic acids, 1a -1d, 2a -2d, and 3a -3d, together with the known compound (4) (Fig.…”

A new bioactive steroidal ketone from the South China Sea sponge Xestospongia testudinaria

“…The animals have been well recognized for the production of various secondary metabolites with intriguing structural features and belonging to diverse structural and biosynthetic classes, such as brominated polyunsaturated lipids [7,8], alkaloids [7] and steroids [9 -11], etc. Previous chemical investigation on the title animal carried out by our group have resulted in the isolation and structure elucidation of eight new brominated polyacetylenic compounds xestonarienes A -H [12].…”