Per Friedrich Wöhler.
The Wöhler synthesis is of great historical significance because for the first time an organic compound was produced from inorganic reactants. This finding went against the mainstream theory of that time called vitalism which stated that organic matter possessed a special force or vital force inherent to all things living. For this reason a sharp boundary existed between organic and inorganic compounds. Urea was discovered in 1799 and could until then only be obtained from biological sources such as urine. Wöhler reported to his mentor Berzelius
"I cannot, so to say, hold my chemical water and must tell you that I can make urea without thereby needing to have kidneys, or anyhow, an animal, be it human or dog".
It is argued that organic chemistry did not actually start with this discovery in 1828 but 4 years earlier with the synthesis of oxalic acid in 1824 also by Wöhler and also from the inorganic precursor cyanogen. It is also argued that vitalism was not put to bed either in 1828. His contemporaries Liebig and Pasteur never abandoned vitalism and it took until 1845 when Kolbe repeated an inorganic – organic conversion of carbon disulfide to acetic acid before vitalism started to lose supporters in serious numbers. https://en.wikipedia.org/wiki/W%C3%B6hler_synthesis