Celebiography.net

George Wittig

Picture of George Wittig

Date of Birth: 06/16/1897

Age: 90

Place of birth: Berlin

Citizenship: Germany

Background

in 1944 he was promoted to full professor and was appointed director of the University of Tubingen Institute of Chemical and finally, 12 years later moved to the University of Heidelberg, where in 1967 he became an honorary professor emeritus.

At the beginning of his career V. interested exact mechanisms of certain reactions, particularly those involving free radicals and carbanions (negatively charged carbon atoms in organic molecules) as an intermediate reaction products, as well as certain types of molecular rearrangements. Development of the scientist created a reputation as an organic chemist with a rich creative imagination and skilled experimenter.

In 40-ies. B. set out to create molecules in which 5 organic groups have covalent bonds with the elements of group V of the periodic table, such as nitrogen, phosphorus and arsenic. Although the creation of such molecules is considered theoretically possible, they are also synthesized no. Eventually B. and colleagues have solved this problem (it is not only failed nitrogen synthesis). In the process of the research scientists are faced with the cause of their interest in compounds called ylides. The quaternary salt ylidene group V element (4 containing organic group attached and halogen) instead acquire fifth organic group loses a proton from the organic group. In 1953, V. found that such free ylides to react with carbonyl compounds (aldehydes and ketones whose molecule contains a carbon-oxygen double bond). This ylide carbanion (devoid of proton carbon) is exchanged for oxygen atom of the carbonyl. In this process the olefin is formed with a new carbon-carbon double bond in place of the carbonyl group. Accidentally made the discovery, now known as the Wittig reaction, possess incomparably great scientific potential than initially successful solution of the problem.

In the 20-ies. independently Hermann Staudinger and Carl S. Marvel have already implemented significant preparatory work for this type of reactions. In fact, the Staudinger described the first phosphorus ylide in 1919, however, since most of their work was not published at the time, she hardly had an impact on the study conducted by AV. The reason for its success VA as it may seem strange, explained the limitations of their knowledge about the work of predecessors, devoted to the study of this topic. Indeed, if the VA aware of the progress made by Marvel, he would receive only compounds containing pentavalent phosphorus, and a new chemical reaction (Wittig reaction) would not have been open. Ironically, Staudinger and B were colleagues at the University of Freiburg in nachale40-ies., But by that time Staudinger has long ceased to work on derivatives of phosphorus, and could not give VA the new information in the field of research.

Wittig organic chemists have adopted immediately. Thanks to it, they are now able to easily and reliably connect Two-carbon structure using the appropriate alkyl halide and a carbonyl compound, and the one and the other can be easily obtained from various starting materials. In addition, the reaction was remarkably easy, giving a high yield and at the same time there had been no unintended molecular rearrangements. So far, it is believed that this reaction is far superior rival with her methods of olefin synthesis.

The utility of this reaction is further increased thanks to further research by V. and a group of his colleagues in the Tubingen and Heidelberg. In the early 60-ies. More than one hundred articles on the specific application of the Wittig reaction to the mid-80s there were already thousands. There are also many technical applications of this reaction.

In 1979, V. and Herbert C. Brown was awarded the Nobel Prize in Chemistry "for the development of new methods for organic synthesis of boron and phosphorus-containing compounds." In his opening speech on behalf of the Royal Swedish Academy of Sciences Bendt Lindberg he said: "George W. has done a lot for the development of organic chemistry ... elegant method B. widely used, for example, in the industrial synthesis of vitamin A