Spirokermeline: A Macrocyclic Spirolactone from Kermadecia elliptica Brongn. & Gris

Abstract

Spirokermeline, a new macrocyclic compound derived from resorcinol, was isolated from Kermadecia elliptica, an endemic species of New Caledonia. The structure of spirokermeline was elucidated on the basis of spectroscopic analysis and X‐ray single‐crystal diffraction analysis. This is the first time that a 3H,3′H‐spiro[benzofuran‐2,1′‐isobenzofuran]‐3,3′‐dione was isolated from higher plants and only the second time that this scaffold was found in nature. A possible biosynthetic pathway is proposed.

Direct synthesis of oxaspirolactones in batch, photoflow, and silica gel-supported solvent-free conditionsviavisible-light photo- and heterogeneous Brønsted acid relay catalysis

“…On the other hand, unsubstituted hydroxy alkylfuran 1n and 1o both provided the desired products, 2n and 2o in 99% and 92% yields. Interestingly, 2o exhibits the [4,5]-oxaspirolactone motif that is found in a number of natural products, such as the aforementioned beshazuenone D and other rare Abies sesquiterpenoids benshazuenone C 5 and abiespiroside A; 4 b,c , 30 in the aspersclerotiorone F, 31 a γ-butenolide derivative from a fungus; and in the anticancer metabolite sequoiamonascin A. 32 Other substrates, including an unsymmetrical diarylated precursor 1p , having phenyl and 2-methylphenyl as appended groups, also underwent our reaction affording an excellent 96% yield in a 1 : 1 diastereomeric ratio.…”

“…A macrocyclic oxaspirolactone was also reported in 2018 with the isolation of the spirokermeline cyclophane. 5 In more structurally complex natural products, the title motif is present in dammarane-type triterpenoids, namely in phainanoids A–F, 6 and in the rearranged triterpenoid spirochensilide A, 7 which possess immunosuppressive and mild anti-inflammatory activities, respectively.…”

In vivo hepatoprotective and nephroprotective effects of Stenocarpus sinuatus leaf extract against ifosfamide‐induced toxicity in rats

“…Furthermore, phytochemical studies have revealed the presence of various classes of compounds in the family members. [35][36][37] Stenocarpus sinuatus (A. CUNN.)…”