Organic Catalysis: A Broadly Useful Strategy for Controlled Polymerization Reactions

本研究的重点是开发应变酯活性开环聚合的通用有机催化策略。亲核卡宾催化剂来自于噻唑、咪唑和咪唑系列，将用于应变环状单体和其他单体体系的聚合。此外，还将利用具有活化的C-H键的咪唑啉-2-叶立丁来研究各种C-H插入反应，以得到空气稳定的卡宾。使用的原位方法将提供快速筛选催化剂文库，以基本了解催化剂结构对聚合速度、控制程度、底物耐受性和这些策略可获得的分子量范围的影响。机理研究将解决单体活化与酯交换反应的相对速率，以确定可预期良好控制聚合的动力学窗口。将这种有机催化方法扩展到内酰胺的开环反应和磷酸酯的酯交换反应也将被研究。通过这一奖项，有机和高分子化学项目和多学科活动办公室支持斯坦福大学化学系的罗伯特·M·韦茅斯博士和IBM研究院的詹姆斯·L·赫德里克博士的GOALI项目。这项合作将把研究重点放在开发用于活性聚合过程的有机催化剂上。该项目将开发可控聚合反应的新合成方法，对酯交换反应的亲核催化获得新的见解，并开发用于精细化学合成的新型有机催化剂。该项目将使研究生和博士后能够在学术实验室和工业实验室之间进行高度跨学科的协作努力，并进一步有可能在创造更清洁的环境方面产生更广泛的影响。

The focus of this research involves the development of general organocatalytic strategy for the living ring opening polymerization of strained esters. Nucleophilic carbene catalysts from thiazolium, imidazolium and imidazolinium families will be examined for the polymerization of strained cyclic monomers and other monomer systems. Further, a variety of C-H insertion reactions will be studied using imidazolin-2-ylidines with activated C-H bonds to afford air stable carbenes. The in situ methodology used will provide for rapid screening of libraries of catalysts to give basic understanding of catalyst structure on polymerization rates, the degree of control, the substrate tolerance and range of molecular weights accessible with these strategies. Mechanistic investigations will address the relative rate of monomer activation versus transesterification to define the kinetic window where well-controlled polymerization can be expected. Extension of this organocatalytic method to the ring opening of lactams and transesterification of phosphate esters will also be investigated. With this award, the Organic and Macromolecular Chemistry Program and the Office of Multidisciplinary Activities are supporting the GOALI project of Dr. Robert M. Weymouth of the Department of Chemistry at Stanford University and Dr. James L. Hedrick of IBM Research. The collaboration will focus research efforts on developing organic catalysts for use in living polymerization processes. The project will develop new synthetic methods for controlled polymerization reactions, obtain new insights into nucleophilic catalysis of transesterification reactions and develop a new class of organocatalysts for use in fine chemical synthesis. The project will enable the training of graduate students and a postdoctoral in a highly interdisciplinary, collaborative effort between an academic and an industrial laboratory and there is further potential for broader impact of the work in terms of creating a cleaner environment.