Development of Novel Photoelectron Transfer Reaction Systems with Stable Organometallic Compounds Promoted by Acids and Bass

研究了在芳香酮的光诱导电子转移(PET)反应中，碱性(亲核)基团对有机金属试剂活化的影响。对于烯丙基和苄基锡试剂，近位羟基的存在提高了反应效率。对于烯丙基硅试剂，引入第5个配体可以有效地促进PET反应，得到高产率的烯丙化产物。这些反应还包含了正电子发射光谱的特征、α区域选择性和烯丙基部分双键的立体保留。类似的硼试剂也通过第四碱性配体与芳香酮进行PET反应，进行烯丙基化和苄基化反应。这些反应是使用硅和硼试剂通过PET进行烯丙化反应的第一个例子。醇溶素类试剂不是很好的PET试剂，但可用于杂原子取代烷基的羰基烷基化反应。此外，高价(5-配位)烷基锡试剂表现出较高的烷基化效率。另一方面，还考察了Lewis酸对PET反应的影响。在酮中加入金属盐加速了烯丙基硅试剂的聚酯反应。另一方面，金属离子抑制了烯丙基锡试剂中PET的氨基部分，选择性地促进了烯丙基锡部分的PET发生羰基烯丙化反应。为了与光反应进行比较，考察了热Lewis酸促进反应。不适合进行热酸反应的含有羟基和氨基的烯丙基锡被成功地应用于光烯丙化反应。这显示了光反应的综合优点。作为热反应的优势，Lewis酸可以通过它们的配位方式来控制烯丙化反应的立体选择性。

The effect of basic (nucleophilic) moieties on the activation of organometallic reagents in the photoinduced electron transfer (PET) reaction toward aromatic ketones was investigated. For allyl- and benzyltin reagents, the presence of hydroxyl group at the near position increased the efficiency of the reaction. For allylsilicon reagents, introduction of the 5th ligand into them accelerated the PET reaction efficiently and gave the allylated product in high yields. These reactions also contained the characteristic feature of PET, α-regioselectivity and stereoretention of the double bond in allyl moiety. Similar boron reagents also underwent PET reaction with aromatic ketones by the 4th basic ligand to perform allylation and benzylation. These reactions are the first examples of allylation via PET using silicon and boron reagents. Alkytin reagents, which were not good reagents for PET, could be applied to the carbonyl alkylation by the substitution of an alkyl by a hetero atom. Furthermore, hypervalent (5-coordenated) alkyltin reagents exhibited high efficiency of alkylation.On the other hand, the effect of Lewis acids to the PET reaction was also investigated. Addition of metal salts to ketones accelerated the PET from allylsilicon reagents. As another topic, metal ion inhibited PET from amino moiety in allyltin reagent and selectively promoted PET from allyltin moiety to undergo carbonyl allylation.For comparison with photoreaction, thermal Lewis acid promoted reaction was investigated. Allyltins containing a hydroxyl and an amino group, which were not suitable for the thermal acidic reaction, were successfully applied to the photoallylation reaction. This shows a synthetic merit of the photoreaction. As an advantage of the thermal reaction, Lewis acids could control stereoselectivity in allylation reaction by their coordination mode.