Total Synthesis of Natural Products of Microbial Origins(Recent Topics of the Agricultunal Biological Science in Tohoku University)

Microorganisms are an important rich source of secondary metabolites, which could be useful leads to valuable agrochemicals and/or medicinal drugs. This mini-review describes our recent achievements on the total synthesis of biologically active natural products of microbial origins: pteridic acids A and B (strong plant growth promoters), epoxyquinols A and B (anti-angiogenic compounds), communiols A-F, G, and H, and macrotetrolide α (antibiotics), pyricuol and tabtoxinine-β-lactam (phytotoxins)

Synthetic studies of ancistrocladinium A and B, antileishmanial compounds isolated from a Congolese Ancistrocladus Species

Synthetic studies of ancistrocladinium A and B, antileishmanial compounds isolated from a Congolese Ancistrocladus sp., are described. Buchwald‒Hartwig coupling reaction between the dihydroisoquinoline and the naphthyl triflate failed. The main framework of ancistrocladinium A was constructed by 1,2‒addition of the amine to the naphthoquinone in the presence of celium trichloride as a catalyst. On the other hand, 1,4‒addition of the amine to the naphthoquinone proceeded without catalyst to form the framework of B. These products will be valuable leads for antileishmanial agents

Formal Total Synthesis of Lactimidomycin

A concise synthesis of an intermediate of lactimidomycin, a glutarimide-containing macrocyclic polyketide produced by an actinomycete, has been accomplished in 35% overall yield from a known vinylketene silyl <i>N</i>,<i>O</i>-acetal by a 10-step sequence that involves two types of asymmetric aldol reactions to install all the stereocenters, the Stille coupling to set up the whole carbon famework, and the Yamaguchi lactonization to construct the 12-membered macrolactone ring

Synthetic studies of ancistrocladinium A and B, antileishmanial compounds isolated from a Congolese Ancistrocladus Species

Synthetic studies of ancistrocladinium A and B, antileishmanial compounds isolated from a Congolese Ancistrocladus sp., are described. Buchwald‒Hartwig coupling reaction between the dihydroisoquinoline and the naphthyl triflate failed. The main framework of ancistrocladinium A was constructed by 1,2‒addition of the amine to the naphthoquinone in the presence of celium trichloride as a catalyst. On the other hand, 1,4‒addition of the amine to the naphthoquinone proceeded without catalyst to form the framework of B. These products will be valuable leads for antileishmanial agents

Synthesis of aurachins B and H

<p>The synthesis of aurachin B, an antibiotic that features a C3-oxygen-substituted quinoline <i>N</i>-oxide nucleus bearing a farnesyl side chain at C4, was accomplished in 60% overall yield from <i>o</i>-nitrotoluene by a concise five-step sequence. An enantioselective synthesis of aurachin H was also achieved for the first time in only two steps from an optically active epoxy iodide.</p

Total Synthesis of Amphirionin‑4

An expeditious enantioselective total synthesis of amphirionin-4, a remarkably potent promoter of the proliferation of ST-2 cells, has been achieved from (±)-(<i>E</i>)-1,4-hexadien-3-ol by an 8-pot sequence that features the Sharpless kinetic resolution, iodoetherification, and the CBS reduction to install the stereocenters, utilization of four one-pot transformations to streamline the synthetic process, and the Stille coupling reaction at nearly the center of the target molecule to complete the total synthesis