In an essay to celebrate the 125th anniversary of Angewandte Chemie our friend and mentor Prof. K. C. Nicolaou had penned an essay for this august event. Which can be seen here.
Not to be outdone in this essay he examines the flow of chemical knowledge from its emergence in the 5th century B.C. to the present day, 2,500 years or so. Stopping along the way of this long journey, he highlights the leading scientific personalities of each age together with their theorems discoveries.
Emerging out of this primordial soup of chemical knowledge is the science of organic synthesis the “Flagship” of which is “the art of total synthesis”. This “Flagship” was launched in the 19th century and sat in the harbour for quite a few decades until the scientists of the day got their collective acts together and came up with atomic theory. I suppose somehow like hitchhikers in the galaxy. Indeed in 1845 two of these eminent thinkers and, more importantly experimentalists put their heads together and came up with the answer to the ultimate question, and it was not “24”.
Laurent and Gerhardt started to unfurl the sails of the flagship, which had been sitting there gathering dust, recognising that the molecules synthesised to that day could be classified into a “homologous” box and a “type” box, the latter assuming that all organic molecules belonged to three different types. This suggestion paved the way for the connection between inorganic and organic chemistry. Kekulé was also busy on the organic side of the Flagship, thinking about structure and writing his 2-volume book “The Chemistry of Benzene Derivatives or the Aromatic Substances”. Much later on Pauling refined these theories in his book “The Nature of the Chemical Bond”. Which I suppose puts him in the middle of the “Flagship”.
Back to Kekulé; in 1860 together with Canizzaro he organised what must have been one of the first international conferences to deal with all the currently contentious ideas of chemistry, so the crew was assembling, with some dissention. But they did agree on atomic weights and chemical formulas. Indeed this august meeting inspired one participant, Mendeléev that he went home and came up with the periodic table.
The “Flagship” hauled anchor around the late half of the 18th century with work by Scheele (isolation) and Wöhler (synthesis). Liebig and his students also populated the crew refining many ideas of the day. Based on the new science of synthesis new industries sprang up. Perkin, trying to synthesise quinine actually obtained the first dyestuff. More of these were prepared and indeed it was said that the wealth of a nation could be measured in the value of Her dyestuff industry. It was a relatively short step from dyes to pharmaceuticals, Aspirin, introduced by Bayer, being the example.
Synthetic organic chemistry emerged as the driving force of the “Flagship” with many new reactions being discovered, mainly from German laboratories and by students or students of students of Liebig. This was helped along its way by the role of the structure of the various compounds. This vital part of chemistry is just as important today as it was then. I suppose the Admiral of the “Flagship” has to be R. B. Woodward, with numerous captains in tow not to mention a successor, E. J. Corey.
Everything considered I found this to be a very interesting perspective on the evolution of organic synthesis and especially the total synthesis of complex molecules. Prof. Nicolaou has done an excellent job in linking the various scientific discoveries over the years to a subject dear to his heart. If you are interested in the timeline of synthesis it is well worth a read.