Total synthesis of the fungal metabolite (±)-acremine G: acceleration of a biomimetic Diels–Alder reaction on silica gel

Synthesis of acremines A, B and F and studies on the bisacremines

The acremines are a family of meroterpenoids isolated from fungi of the genus Acremonium. Here, we present the asymmetric total synthesis of acremine F which hinges on a modestly enantioselective dihydroxylation and a subsequent kinetic resolution via a highly selective asymmetric reduction. Chemoselective oxidation of acremine F gave access to acremines A and B. The dimerization of acremine F to bisacremine E was investigated but could not be achieved, shedding light on the formation of the acremine dimers in nature.

Diversity-Oriented Synthesis of Spiroannulated Benzofuran-3-one Scaffold of Leptosphaerin C and Congeners via Aryne Insertion

A concise synthesis of functionalized cyclohexenone-fused spirobenzofuran-3-ones under mild reaction conditions was developed. The reaction proceeds via insertion of aryne into the C-O bond followed by a regioselective intramolecular conjugate addition. The use of silyl-protected acid was crucial for the transformation. This protocol was successfully applied for the synthesis of leptosphaerin C core and its novel analogues.

Synthetic studies en route to the first total synthesis of a naturally occurring quinone from Acorus gramineus, iso-merrilliaquinone, iso-magnoshinin and 2-epi-3,4-dihydro magnoshinin

An elegant Diels–Alder based approach has been demonstrated for the first racemic total synthesis of gramineusquinone B, iso-merrilliaquinone, iso-magnoshinin and 2-epi-3,4-dihydro magnoshinin.

Bisacremines E-G, Three Polycyclic Dimeric Acremines Produced by Acremonium persicinum SC0105

Three dimeric acremines, bisacremines E-G (1-3), with an unusual carbon skeleton were isolated from cultures of the soil-derived fungus Acremonium persicinum SC0105. Their structures were elucidated by spectroscopic analysis, X-ray diffraction, and ECD/TDDFT computations. Compound 3 exhibited inhibitory effects on the production of TNF-α, IL-6, and NO in LPS-stimulated macrophages. A biogenetic pathway with a [4 + 2] cycloaddition as the key reaction is proposed for 1-3.

Bisacremines A-D, Dimeric Acremines Produced by a Soil-Derived Acremonium persicinum Strain

Four dimeric acremines, bisacremines A-D (1-4), with a novel carbon skeleton and a new monomer, acremine T (5), were obtained from cultures of the soil-derived fungus Acremonium persicinum SC0105. Their structures were characterized by analysis of spectroscopic data, ECD/TDDFT computations, and X-ray diffraction. Compounds 1 and 2 exhibited weak cytotoxicity against HeLa cells, and 2 also showed modest activity against A549 and HepG2 cells.