Tuning Oxocarbenium Ion and Acyl Iminium Ion Reactivity and Stereoelectronics

在这个由化学系化学合成计划资助的项目中，威廉玛丽学院的Robert J. Hinkle教授将探索高反应性亲核试剂攻击环状氧碳正离子的立体化学偏好。 虽然通过氧代碳正离子形成的C-糖苷已被用于一些全合成中，但控制面选择性的因素尚不清楚，并且高反应性烯醇醚和烯酮甲硅烷基缩醛亲核试剂发生选择性的显著侵蚀。将对电子偏置的、完全取代的氧碳鎓碳原子进行研究，以确定反应是否通过SN 1样或SN 2样机制发生。 更广泛的影响主要涉及培训学生，同时通过将许多本科生和硕士研究人员纳入该项目来扩大参与。这里的活动将继续在威廉玛丽学院培养一个强大的，包容性的，主要是本科课程。 建立控制亲核试剂对环状氧碳正离子的方法中的表面选择性的因素可以导致在有价值的C-糖苷的合成中更大的、更可预测的立体控制。这些环状结构是具有抗癌、抗菌等生物活性的化合物中的常见元素。在这项研究中开发的技能将适用于各种各样的化学工作，如与制药和农业有关的工作，以及改进催化剂和开发生物探针的研究;所有这些活动都需要有机分子的受控合成。 最后，该项目将为本科生和硕士生提供优秀的机械和合成培训，包括那些历史上在物理科学中代表性不足的群体。

In this project funded by the Chemical Synthesis Program of the Chemistry Division, Professor Robert J. Hinkle of the College of William & Mary will explore the stereochemical preferences for attack of highly-reactive nucleophiles on cyclic oxocarbenium ions. Although formation of C-glycosides via oxocarbenium ions has been utilized in a number of total syntheses, the factors governing facial selectivity are not clear and significant erosion of selectivity occurs with highly-reactive enol ether and ketene silyl acetal nucleophiles. Studies on electronically biased, fully-substituted oxocarbenium carbon atoms will be undertaken to determine if the reactions are occurring via SN1-like, or SN2-like mechanisms. The broader impacts primarily involve training students while broadening participation through the inclusion of numerous undergraduate and Master's researchers on the project. The activities herein will continue to foster a strong, inclusive, predominantly undergraduate program at the College of William & Mary. Establishing the factors which govern facial selectivity in the approach of nucleophiles on cyclic oxocarbenium ions could lead to greater, and more predictable, stereocontrol in the synthesis of valuable C-glycosides. These ring structures are common elements in a vast number of compounds possessing anti-cancer, antibiotic and other biological activities. The skills developed in this research will be applicable to a wide variety of chemical endeavors such as those relating to the pharmaceutical and agricultural industries as well as research to improve catalysts and develop biological probes; all of these activities require the controlled syntheses of organic molecules. Finally, this project will provide excellent mechanistic and synthetic training for undergraduate and Master's students, including those from groups historically underrepresented in the physical sciences.