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| German
chemist whose method of synthesizing olefins (alkenes) from carbonyl compounds
is a reaction often termed the Wittig synthesis. For this achievement he
shared the 1979 Nobel Prize for Chemistry. Wittig was born in Berlin and studied at Kassel and Marburg. He was professor at Freiburg 1937-44, Tübingen 1944-56, and Heidelberg 1956-67. In the Wittig reaction, which he first demonstrated 1954, a carbonyl compound (aldehyde or ketone) reacts with an organic phosphorus compound, an alkylidenetriphenylphosphorane, (C6H5)3P=CR2, where R is a hydrogen atom or an organic radical. The alkylidene group (=CR2) of the reagent reacts with the oxygen atom of the carbonyl group to form a hydrocarbon with a double bond, an olefin (alkene). In general: (C6H5)3P=CR2 + R2'CO (C6H5)3PO + R2C=CR2 The reaction is widely used in organic synthesis, for example to make squalene (the synthetic precursor of cholesterol) and vitamin D3. |