Fenestrane Approach Toward Planar Tetracoordinate Carbon

本研究中对一些被称为“芬内酯和/或芬内酯”的张力分子的合成的研究将提高对这类化合物的键合特性的理解。12 -环烯（1,3,5,7,9,11-己烯）和14 -环烯-ı5.5.6.6.！七烯烷对碳的成键特性有重要影响。在四面体碳的“平面化”方法中，为了比较，选择了提供键角变形/应变能逐渐增加的目标。初步研究将重点放在合成ı5.5.5.5！fenestrenes, （tccc）和（tctc），以及ı5.5.6.6！从上述分子的合成中获得的知识将用于研究更具活性的ı5.5.5.5芬内酯。此外，研究戊烯烷环烯的合成将有助于确定Huckel pi离域是否在这种多烯环烯的稳定性中起作用；这些环烯主要由融合的五元环组成。对各种窗内酯进行各种复杂程度的计算，提供了精确的键长和键角，可以与x射线结构进行比较，在应变系统中没有实验热化学数据来评估计算方法的准确性。对目标分子的化学/反应性的研究将提供对有机分子中碳化学键性质的深入了解，特别是关于碳原子的应变和角度变形可能会影响杂化的变化。有机合成计划支持詹姆斯·m·库克博士继续研究。该研究将通过构建具有高度扭曲结构的分子来更好地理解应变对碳框架的影响。这有可能为如何有效地操纵化学反应性提供更深入的见解。

The study of the synthesis of a number of strained molecules, termed "fenestranes and/or fenestrenes" in this investigation will improve the understanding of the bonding character in such compounds. The synthesis and study of the 12 pi annulene (staurane-1,3,5,7,9,11-hexaene) and the 14 pi-ı5.5.6.6.! fenestrane heptaene are important in terms of the bonding character of carbon. In the approach toward "planarization" of tetrahedral carbon, the targets have been chosen to provide a gradual increase in bond angle deformation/strain energy for purposes of comparision. Initial research will focus on the synthesis of the ı5.5.5.5!fenestranes, (tccc) and (tctc), as well as ı5.5.6.6!fenestrenes. Knowledge gained from synthesis of the above molecules will then be employed for the study of the more reactive ı5.5.5.5!fenestrenes. In addition, investigation of the synthesis of fenestrane annulenes will help to determine if Huckel pi-delocalization plays a role in the stability of such polyquinene annulenes; these annulenes are primarily composed of fused five-membered rings. Calculations at various levels of sophistication for a variety of these fenestranes have provided accurate bond lengths and bond angles where comparison with X-ray structures is possible, there are no experimental thermochemical data in strained systems for evaluation of the accuracy of the computational methods. Studies of the chemistry/reactivity of the target molecules will provide much needed insight into the nature of the carbon chemical bond in organic molecules in general, and in particular with respect to carbon atoms where strain and angle deformation may effect a change in hybridization. The Organic Synthesis Program is supporting the continuation of the studies of Dr. James M. Cook. The research will provide greater understanding of the effect of strain upon the carbon framework by the construction of molecules which have highly distorted structures. This has the potential to provide deeper insight into how chemical reactivity can be usefully manipulated.