In an effort to prepare for one of my lectures (I start my segment of CHM 440 next week), I needed to come up with an impressive example of academic innovation that has made a difference in industry and was rapidly adopted. In particular, I was seeking a case of a chemoselective transformation. It did not take me long to find one among the papers I have collected over the years. I want to share it with you tonight as I think this is a marvelous case of a reaction that is mechanistically simple, yet immensely useful. The story relates to Taxol (paclitaxel) and its isolation from the bark of the Pacific yew. Unlike this very slow-growing tree, the nursery-grown ornamental yews from Michigan’s Upper Peninsula were found to mature in just a few years and could be easily regenerated, making the overall process sustainable. These little guys contained predominantly six primary taxane constituents characterized by structurally different amides in the side chain (shown below). Some years ago, Professor Bruce Ganem of Cornell University developed a process for chemoselective reduction of amides using Schwartz’s reagent. The Zr-O interaction features prominently in this chemoselective process, which was put to good use in the case of yew tree extracts. Hydrolysis and benzoylation of the imines produced during the reduction afforded the ultimate paclitaxel. I would say this is a rather dramatic example of academic innovation that has been rapidly adopted in industry.
http://pubs.acs.org/doi/abs/10.1021/jo070129s