Design of Fine Acid Base Catalysts and their Utility in Selective Organic Synthesis

在本研究项目中，我们将重点放在合理设计真正高效的酸/碱催化剂上，以开发合成工艺，以达到普通酸/碱催化剂无法观察到的高反应活性和选择性。在复杂的Lewis酸化学中，成功设计了一种新的手性双齿Ti（IV）配合物，该配合物可用于醛羰基的同时配位，从而允许对这些羰基进行精确的对映面辨别，从而实现一种新的催化的、实用的对映选择性醛与烯丙基三丁基锡的烯丙基化。该手性双齿Ti（IV）配合物已成功应用于硝基或重氮乙酸酯的不对称1,3 -偶极环加成。另一方面，相转移催化是一种非常有用的方法，通常涉及简单的实验操作，温和的反应条件，廉价和环保的试剂和溶剂，以及大规模的反应。因此，从市售的(S)-或(R)-联萘酚中提取的结构刚性的手性螺氨盐被设计为新的c_2对称手性相转移催化剂，并成功地应用于温和相转移条件下的高效、催化对映选择性合成。最近，我们成功地设计了简化的，但非常活跃的手性相转移催化剂，用于α-烷基和α，α-二烷基氨基酸的实际不对称合成。此外，还设计了手性、螺旋型相转移催化剂，用于大规模生产空间位阻α-烷基胺的不对称Strecker反应。可以制备碗状的有机金属主体，三（2,6 -二苯基苄基）-硅基，-germyl和-锡化合物，并将其应用于选择性有机转化。

In this research project, we focused our attention on the rational design of truly efficient acid/base catalysts for the development of synthetic processes in order to achieve the high reactivity and selectivity, not observable by ordinary, acid/base catalysts. In the sophisticated Lewis acid chemistry, a new, chiral bidentate Ti(IV) complex was successfully designed and can be utilized for simultaneous coordination to aldehyde carbonyls, thereby allowing the precise enantioface discrimination of such carbonyls for a new catalytic, practical enantioselective allylation of aldehydes with allyltributyltin. This chiral bidentate Ti(IV) complex has been successfully applied to asymmetric 1, 3-dipolar cycloaddition of nitrones or diazoacetates. On the other hand, phase transfer catalysis is a very useful approach that typically involves simple experimental operations, mild reaction conditions, inexpensive and environmentally benign reagents and solvents, and the large-scale reactions. Accordingly, structurally rigid, chiral spiro ammoniurn salts derived from commercially available (S)- or (R)-binaphthol have been designed as new C_2-symmetric chiral phase transfer catalysts and successfully applied to the highly efficient, catalytic enantioselective synthesis under mild phase transfer conditions. Quite recently, we have successfully designed simplified, yet very active chiral phase transfer catalysts for practical asymmetric synthesis of α-alkyl- and α,α-dialkylamino acids. In addition, chiral, helical-type phase transfer catalysts were newly designed for effecting asymmetric Strecker reaction for large-scale production of sterically hindered α-alkylamino acids. A bowl-shaped organometallic host, tris(2, 6-diphenylbenzyl)-silyl, -germyl, and -tin compounds can be prepared, and applied to selective organic transformations.