Fundamental Research for Developing Organotin Reagent

为了确定有机锡化合物作为合成试剂的实用性，研究得出了以下新的发现。(1)。Pd(O)催化偶联反应在杂芳烃中的应用。在Pd(PPh_3)_4存在下，噻吩基和吡啶溴化物能与溴苯反应的有机锡试剂发生偶联反应，而与需要PdCl2(Po-Tol_3)_2催化剂的锡化合物不能偶联。噻吩基和吡啶基化合物与杂芳基溴化物的偶联为合成杂二芳基、杂四芳基和杂季芳基化合物提供了很好的工具。(2)。过渡金属络合物催化的过渡金属体系偶联反应。有机锡和卤化物在钯的催化下发生了插入第三组分异腈和降冰片烯的偶联反应，分别得到亚胺和外，顺-2，3-二取代降冰片。(3)。在等摩尔量的TiCl4存在下，通过与TiCl4.2-锡甲酸酯的转金属加成反应，可与醛反应生成伽马内酯。锡酰胺、2-(2-锡基)吡啶和N-锡基-对中氧基丙酮的反应相似。反应通过转金属反应进行，得到了由N或O分子内配位稳定的钛化合物。

Research to establish the utility of organotin compounds as synthetic reagents gave the following new findings. (1). Application of Pd(O) catalyzed coupling reaction to heteroaromatics. Thienyl and pyridyl bromide were fond to couple with organotin reagents which can react with bromobenzene in the presence of Pd(PPh_3)_4, but not with those tin compounds which need the catalyst PdCl_2(Po-tol_3)_2 for the coupling with bromobenzene. The coupling of thienyl and pyridyltin compounds with heteroaryl bromides provides good tools for syntheses of heterobiaryls, heteroteraryls, and heteroquateraryls. (2). Coupling reactions of temary systems catalyzed by transition metal complexes. Coupling reactions of organotins and halides involving insertion of third components such as isonitrile and norbornene were found to take place under catalysis of palladium, giving imines and exo,cis-2,3-disubstituted norbomane, respectively. (3). Addition to carbonyls via transmetalation with TiCl_4.2-Stannylcarbonylates were found to react with aldehydes in the presence of equimolar amount of TiCl_4. The reaction giving gamma-lactones after hydrolytic treatment. Stannylamide, 2-(2-stannyl)pyridine and N-stannyl-p- medioxypropiophenone reacted similarly. The reaction proceeds via transmetalation giving titanium compounds stabilized by intramolecular coordination of N or 0 to Ti.