Aus dem Tryptophanderivat (I) wird auf dem im Formelschema angegebenen Weg das Trypargin (VIII) hergestellt.

We prepared novel planar chiral monophosphine ligands bearing ferrocene-triazole backbones. These ligands were produced in a series of steps that included triazole synthesis by diastereoselective azidation and Huisgen cycloaddition of (S)-Ugi's amine, followed by methylation and phosphine introduction. This method was applicable to the preparation of various analogues due to the wide substrate scope of the Huisgen cycloaddition reaction. These ligands showed good catalytic activity in Suzuki-Miyaura coupling reactions, especially those involving bulky substrates. Furthermore, the optically active versions of these ligands were used in the asymmetric Suzuki-Miyaura coupling reaction to produce the axial chiral binaphthyl compound with moderate enantioselectivity. The ligand developed in this study is the first triazole-type biaryl-monophosphine ligand that can be used in asymmetric reactions, and it is expected to be a new tool for the accessing chiral compounds.

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A Facile Cyclopropanol Synthesis from β-Halo Ester with Grignard Reagent. Samarium(II) Diiodide Couple. -Ethyl β-bromopropionate (I) undergoes samarium diiodide-promoted cyclization reaction with the Grignard compounds (II) to produce the 1-substituted cyclopropanols (III) which are converted into the trimethylsilyl ethers (V). (Mechansim). -(FUKUZAWA, S.; NIIMOTO, Y.; SAKAI, S.; Tetrahedron Lett. 32 (1991) 52, 7691-7694; Dep. Appl. Chem., Fac. Sci. Eng., Chuo Univ., Kasuga, Tokyo 112, Japan; EN)