Solid-Phase Synthesis of Chiral Silicon-Based Reagents and Their Application to Organic Synthesis

为了有效地构建由光学活性有机分子组成的大的化学库，人们开发了用于有机合成的新的合成中间体和试剂。本课题的研究结果总结如下：(1)通过钯催化的光学活性烯丙基醇的固相分子内双硅烷化反应合成了聚合物键合的光学活性烯丙基硅烷。由此得到的烯丙基硅烷与亲电试剂反应，得到了高对映体富集醇和环醚。(2)硅基硼烷与各种不饱和有机分子，包括乙烯基环丙烷和端烯反应，合成了含硅和硼的新有机分子。用手性膦配体与钯配合物进行了端烯对映体选择性硅硼化反应，得到了高效的富含对映体的2-苯基烯丙基硅烷，作为新的2-b…。更多的丙烯酰化试剂用于合成官能化的有机硼化合物。(3)在钯催化剂存在下，氰基硼烷可以加成碳-碳三键。该反应为合成高取代α，β-不饱和腈提供了一条独特的途径，为合成高取代度的不饱和腈提供了方便的试剂。(4)在有机合成中，氨基硼烷是一种新型的亚胺离子发生器。该试剂可以避免酸性反应条件，而酸性反应条件通常是通过形成亚胺离子中间体进行胺化反应所必需的。在非酸性条件下，1，2-二异氰苯衍生物与旋光活性的芳基钯(II)配合物聚合，生成光学活性的聚(喹恶啉-2，3-二基)S，其选择性可达&gT；90%。较少

New synthetic intermediates and reagents for organic synthesis have been developed in response to the demands for the efficient construction of large chemical libraries consisting of optically active organic molecules. The results of this research projects are summarized below.(1)Polymer-bound optically active allylsilanes were synthesized via palladium-catalyzed solid-phase intramolecular bis-silylation of optically active allylic alcohols. Thus obtained allylsilanes were found to react with electrophiles, giving highly enantioenriched alcohols and cyclic ethers stereoselectively.(2)Silylboranes react with various unsaturated organic molecules including vinylcyclopropane and terminal allenes, leading to the synthesis of new organic molecules that contain silicon and boron. Enantioface-selective silaboration of terminal allenes has been developed by using chiral phosphine ligands with palladium complexes, affording enantio-enriched 2-borylallysilanes efficiently, which serve as new 2-b … More orylallyllation reagents for the synthesis of functionalized organoboron compounds.(3)Cyanoboranes were found to add to carbon-carbon triple bonds in the presence of palladium catalysts. The reaction provides a unique access to 2-borlyacrylonitriles, which serves as convenient reagents for the synthesis of highly substituted α,β-unsaturated nitriles.(4)Aminoboranes serve as new iminium ion generators in organic synthesis. The reagent allows to avoid acidic reaction conditions, which are usually required for the amination reactions that proceed via the formation of iminium ion intermediates. Strecker reaction, Mannich reaction and reductive amination reactions proceed in the presence of aldehydes, nucleophiles, and aminoboranes under non-acidic reaction conditions.(5)As a related research project, a new screw-sense selective polymerization reaction has been developed Polymerrization of 1,2-diisocyanobenzen derivatives proceeded with optically active arylpalladium(II) complexes, leading to the formation of optically active poly(quinoxaline-2,3-diyl)s. The selectivity reaches >90% screw-sense excesses when structurally well-tuned chiral organopalladium initiators were used. Less