Stereocontrol utilizing intermolecular interaction

分子间相互作用的动态控制是实现高度立体控制反应的必要条件。基于对分子间反应控制因素的新认识，我们开发了各种新的立体控制反应。(1)金属salen配合物的研究金属salen配合物的x射线结构分析表明，salen配体的构象受到弱键相互作用（如OH-π和CH-π相互作用）以及供体配体的存在或不存在的强烈影响。有了这些知识，首次实现了高度顺式和对映体选择性的环丙烷化。此外，还介绍了新型光活化不对称催化剂，并利用这些配合物开发了以分子氧为末端氧化剂的催化不对称氧化反应。(2)利用新型铝和硼烷试剂进行立体定向和区域选择性环氧环开环的新方法，使连续不对称中心的构建更加高效。高效的手性季碳结构也得到了发展。以这些反应为关键步骤，以非常直接的方式合成了各种复杂结构的天然产物。(3)基于烯醇酯结构动态手性的不对称诱导在没有任何外部手性源的情况下，以对映特异性的方式实现了光学活性α-氨基酸的直接α-烷基化。新引入的含有对氨基吡啶片段的核物理催化剂使高度对映体分化的酰化。观察到的选择性的起源归因于对映体选择性加速。(4)立体选择性碳水化合物合成中的过渡金属催化剂利用过渡金属催化剂，以受保护和未受保护的葡聚糖为原料，高效地合成了多种碳水化合物衍生物。(5)以手性二溴化二萘基锡为催化剂，通过单酰化反应有效地实现了中位二元醇的不对称脱对称。在没有任何外部手性源的情况下，旋光性α-氨基酸通过相应的酰基铵离子转化为旋光性动物。这些结果表明，手性记忆可以在通过羰基中间体进行的反应中观察到。少

Dynamic control of intermolecular interaction is indispensable for achieving highly stereocontrolled reactions. We have developed various new stereocontrolled reactions on the basis of new knowledge on the factors controlling intermolecular reactions.(1) Study with metallosalen complexesThe X-ray structural analysis of metallosalen complexes clarified that conformation of the salen ligands is strongly influenced by weak-bond interactions such as OH-π and CH-π interactions and by the presence or absence of a donor ligand. With this knowledge, highly cis- and enantio-selective cyclopropanation was achieved for the first time. Furthermore, new type of asymmetric catalysts activated by photo-irradiation were introduced and, with these complexes, catalytic asymmetric oxidation using molecular oxygen as the terminal oxidant was developed.(2) New methodologies for acyclic stereocontrolStereospecific and regioselective epoxide-ring opening using new aluminum and borane reagents enabled efficie … More nt construction of consecutive asymmetric centers. High efficient construction of chiral quaternary carbons was also developed. With these reactions as key steps, various natural products of complex architectures were synthesized in a highly straightforward manner.(3) Asymmetric induction based on dynamic chirality of enolate structureDirect α-alkylation of optically active α-amino acids was achieved in an enantiospecific manner in the absence of any external chiral sources. Newly introduced nucleophylic catalyst bearing p-aminopyridine moiety enabled highly enantiomer-differentiating acylation. The origin for the observed selectivity was attributed to enantiomer-selective acceleration.(4) Transition metal catalysts in stereoselective carbohydrate synthesisVarious carbohydrate derivatives were synthesized efficiently from protected and unprotected glucals by using transition metal catalysts.(5) Desymmetrization of meso-diols and memory of chirality in carbenium ionAsymmetric desymmetrization of meso-diols was achieved efficiently by mono-acylation using chiral binaphthyltin dibromide as a catalyst. Optically acive α-amino acids were converted into optically active aminals via the corresponding acylinium ions in the absence of any external chiral sources. These results disclosed that memory of chirality can be observed in the reactions proceeding through a carbenium intermediate. Less