パラジウムを用いる有機合成

アセチレンへのOH, NH, COOHの分子内付加反応

抄録

Various heterocycles are prepared from alkynylamines, alcohols, and carboxylic acids under catalytic action of Pd (II) species. The key reactions are intramolecular addition of NH, OH or COOH to acetylene moiety. Intermediary alkenylpalladium species are protonolyzed or coupled with allyl halides affording organic compounds under the recovery of pd (II) species. During the transformation, Pd (II) species are not reduced, therfore the catalyst can recycle without reoxidation of palladium catalyst which is often observed by the use of olefinic starting materials. Prepared heterocycles are : pyrroles, furans, 1-pyrolines, tetrahydropyridines, dihydrofurans, dihydropyrans, and intramolecular acetals. Syntheses of some insect pheromones bearing intramolecular acetal linkage are also described.