Masaaki Miyashita

Synthetic studies on polypropionate antibiotics based on the stereospecific methylation of γ δ-epoxy acrylates by trimethylaluminum. A highly stereoselective construction of the eight contiguous chiral centers of ansa-chains of rifamycins

Abstract A highly stereoselective construction of the eight contiguous chiral centers of ansa-chains of rifamycins has been accomplished by the iterative use of the stereospecific methylation of γ,δ-epoxy acrylates by trimethylaluminum which was recently developed by us. The present work demonstrates the synthetic potential of the method for the synthesis of polypropionate antibiotics including ansamycins and macrolides.

Synthetic studies on spider neurotoxins (I): total synthesis of nephilatoxins (NPTX-9) and NPTX-11), new neurotoxins of Joro spider (Nephila clavata)

Abstract The first and efficient synthesis of Nephilatoxins (NPTX-9 and NPTX-11), new neurotoxins of Joro spider ( Nephila clavata ), has been achieved by employing a key azide intermediate as the polyamine unit.

Enantioselective synthesis of (−)-serricornin, a sex pheromone of a female cigarette beetle (Lasioderma serricorne F.)

Abstract (−)-Serricornin, a sex pheromone of a cigarette beetle (Lasioderma serricorne F.), has been synthesized highly stereoselectively starting from (Z)-4-benzyloxy-2-buten-1-ol by employing the Katsuki-Sharpless asymmetric epoxidation and two stereospecific methylation reactions, the regioselective γ-methylation of a γ,δ-epoxy acrylate by trimethylaluminum and α-methylation of a δ-lactone, as key steps.

Synthesis of monoterpene lactones, (+)-boschnialactone and (+)-isoiridomyrmecin, starting from l-(+)-arabinose

Abstract A new method for the preparation of optically active γ-substituted α,β-unsaturated δ-lactones as the useful chiral building blocks for natural product synthesis, starting from l -(+)-arabinose and synthesis of two monoterpene lactones, (+)-boschnia-lactone and (+)-isoiridomyrmecin, by the use of these building blocks are described.

Total synthesis of Nephilatoxin-7 (NPTX-7), a new neurotoxin of Joro spider (Nephila clavata)

Abstract The first and highly efficient total synthesis of Nephilatoxin-7 (NPTX-7), a new neurotoxin of Joro spider ( Nephila clavata ), has been achieved by employing the azide strategy wherein the three characteristic polyamine components of the toxin, cadaverine and bis-putreanine, were efficiently constructed by the iterative use of key azide intermediates.

Cunninghamic acids A and B, novel bis(labdane)-type diterpenoids from Cunninghamia lanceolata

Abstract Cunninghamic acids A and B, two novel bis(labdane)-type diterpenoids have been isolated as their methyl esters from the cones of Cunninghamia lanceolata and their structures have been elucidated by extensive analysis of 2D NMR spectroscopy.

A stereocontrolled enantiospecific route to tirandamycin B

The enal 15 was synthesized in enantiomerically pure form starting from (S)-3-benzyloxy-2-methylpropanol 3 via highly regio- and stereo-selective methylation of the γ,δ-epoxy acrylate 5 with trimethylaluminium in the presence of water, developing an enantiospecific route to tirandamycin B.