Bringing Efficiency to Materials Synthesis: The Philosophy of Click Chemistry

Abstract

We open this Essay by paying homage to Sir John Cornforth, who was inspirational to the establishment of click chemistry as one of the most rapidly growing areas of research in materials synthesis. In two distinct ways, the influence of this giant of 20th century chemistry was of fundamental and practical importance. First, the philosophy of Professor Cornforth permeates modern materials chemistry. Cornforth saw himself as a molder of basic building blocks, ‘As a carpenter or carver learns to work with the grain of wood or bone, I learned that each substance has its own nature and can be easy or difficult to handle according to the procedure chosen’.[1] In addition, Cornforth appreciated the goal of efficiency in chemical synthesis, ‘The ideal chemical process is that which a one-armed operator can perform by pouring the reactants into a bath tub and collecting pure product from the drain hole’. Modularity and efficiency are inherent in polymer synthesis, but the explicit appreciation by Cornforth of the importance of both in the preparation of complex, multifunctional systems helped to inaugurate an important era of modern materials chemistry. Second, in 2002 the inaugural Cornforth Symposium was held at the University of Sydney and two of us (Sharpless and Hawker) were honored to be the inaugural lecturers. While polymer chemistry was recognized from the first as an important inspiration for (and potential beneficiary of) the click concept,[2] it was during the symposium and surrounding discussions that the real promise of click chemistry in materials synthesis first began to be appreciated. Initial scribbling of possible research directions quickly became firm outlines of a series of collaborative studies between the Scripps groups and the Hawker group, and these studies helped to lay the foundation for the exploitation of azide/alkyne coupling as a valuable new synthetic technique in synthetic chemistry. A two-way exchange