Geometrical Aspects of the Activation of Carbonyls by Lewis Acids

羰基/刘易斯酸配合物在饱和酮的亲核加成反应、烯酮的共轭亲核加成反应和2 + 4环加成反应中的中间几何结构将被研究。通过使用精心设计的金刚烷酮、癸酮和立体定向癸酮系统，将通过测量结合程度和由此产生的对化学反应活性的影响来研究各种路易斯酸与羰基中心的受控pi结合。对于路易斯酸与酮段结合在平面内以及通过pi-络合物型几何结构的体系，将测量1,2-和1,4-亲核加成物和2 + 4环加成物的反应速率。将评估过渡族和主族金属基路易斯酸之间的差异，并定义饱和羰基和不饱和羰基对路易斯酸络合几何的热力学偏好的影响。现代化学研究的一个最重要的方面是在分子水平上确定加速反应的因素，并提供清洁、有效地产生特定的目标产品。这项来自有机动力学计划的拨款支持怀俄明大学R. C. Corcoran教授对三种重要化学反应的酸催化的持续研究。该研究的目标是合成具有几何约束的化学物质，提供特定的金属酸催化剂结合。这些过程对于设计具有更高效率的新催化剂至关重要，并且对于控制具有重要技术意义的合成过程具有重要意义。

The intermediate geometry of carbonyl/Lewis acid complexes in reactions encompassing nucleophilic addition to saturated ketones, the conjugate nucleophilic addition to enones, and 2 + 4 cycloadditions will be investigated. By use of carefully designed adamantone, decalone, and sterically-directed decalone systems, the controlled pi-binding of a variety of Lewis acids to the carbonyl center will be studied by measuring the extent of binding and the resultant effect on chemical reactivity. The reaction rates of 1,2- and 1,4- nucleophilic additions and 2 + 4 cycloadditions will be measured for systems in which Lewis acid binding to the ketone moiety is in-plane with the ketone as well as via a pi-complex type geometry. Differences between transition and main group metal based Lewis acid will be evaluated, and the effect of saturated versus unsaturated carbonyls on the thermodynamic preference for Lewis acid complexation geometry will be defined. %%% One of the most important aspects of modern chemical research is to define on a molecular level the factors which accelerate reactions and provide for clean, efficient generation of specific targeted products. This grant from the Organic Dynamics Program supports the continuing investigation of the acid catalysis of three important classes of chemical reactions by Professor R. C. Corcoran at the University of Wyoming. The investigation is targeted toward synthesis of chemical species with geometrical constraints that provide specific binding of metallic acid catalysts. Such processes are critical in designing new catalysts with increased efficiency, and will be of significant benefit in controlling synthetic processes of technical importance.