Dr MacMillan came from the other end of the problem. He wanted to remove the metal (in this case copper) from the catalyst involved in a different process, the Diels–Alder reaction.

麦克米伦博士来自问题的另一端。他想从另一个过程——狄尔斯-阿尔德反应（Diels-Alder reaction）中的催化剂中去除金属（在这种情况下是铜）。

Dr MacMillan found he could catalyse Diels-Alder reactions using a type of metal-free molecule called an imidazolidinone to activate the two-carbon component, meaning that it combines enthusiastically with its four-carbon compadre.

麦克米伦博士发现，他可以使用一种名为咪唑烷酮的无金属分子来催化狄尔斯-阿尔德反应，以激活双碳成分，这意味着它可以与其四碳化合物结合。