Enantioselective Allylmetal-Aldehyde, -Acetal and Aldol Reactions

本项目包括三个子项目，在第一个项目中，将使用三个模型来探索环氧硅烷与醛反应中的过渡结构偏好。将研究双键取向、Lewis酸的作用和手性Lewis酸的面部偏好。第二个分项目将开发一般合成方法，包括使用有机锡试剂作为亲核剂，用于手性缩醛的立体选择性开环。第三个研究领域包括开发一类基于应变释放Lewis酸度的新型手性Lewis酸，发明一种催化不对称Aldol缩合反应，研究一种金属环丁烷催化醛的不对称烯丙化反应，以及制备一种利用五配位硅酸盐配合物进行醛的不对称烯丙化反应的试剂。%有了这一续期奖，合成有机计划正在支持伊利诺伊大学厄巴纳分校化学系的Scott E.Denmark博士的研究。本研究的主要目的是：1)阐明在一类重要的硅化合物反应中影响立体化学控制的因素；2)扩大有机锡试剂的合成用途；3)开发不对称合成的新催化反应。不对称合成可以从一系列复杂的原料中优先合成多种产物中的一种，这对有机大分子的高效合成至关重要。

This project contains three subprojects, in the first of which three models will be used to probe the transition structure preferences in the reaction of enoxysilanes with aldehydes. Double bond orientation, the role of Lewis acids and facial preferences with chiral Lewis acids will be studied. The second subproject will develop general synthetic methodology involving the use of organotin reagents as nucleophiles for stereoselective opening of chiral acetals. The third area of study involves development of a new class of chiral Lewis acids based on strain-release Lewis acidity, the invention of a catalytic asymmetric aldol condensation, the study of a catalytic asymmetric allylation of aldehydes using metallacyclobutanes and preparation of a reagent for asymmetric allylation of aldehydes using pentacoordinate siliconate complexes. %%% With this renewal award, the Synthetic Organic Program is supporting the research of Dr. Scott E. Denmark of the Department of Chemistry at the University of Illinois, Urbana. The primary objectives of the research are: 1) to elucidate those factors responsible for stereochemical control in an important family of reactions of silicon compounds 2) to expand the synthetic utility of organotin reagents, and 3) to develop new catalytic reactions for asymmetric synthesis. Asymmetric synthesis leads to the preferential production of only one of the many products possible from reactions of a complicated set of starting materials, and is of critical importance for the efficient synthesis of large organic molecules.