Sir Derek Harold Richard Barton was a British physical chemist and Nobel Prize Laureate.

He was born on 8 September 1918, son of William Thomas and Maude Henrietta Barton. In 1938 he entered Imperial College, University of London, where he graduated in 1940 and obtained his Ph.D. in Organic Chemistry in 1942. From then to 1944 he was a government research chemist, from 1944 to 1945 he was with Albright and Wilson in Birmingham. He then became assistant lecturer in the Department of Chemistry of Imperial College, and from 1946 to 1949 he was ICI Research Fellow. During 1949 and 1950 he was Visiting Lecturer in the Chemistry of Natural Products, at Harvard University, and was then appointed Reader in Organic Chemistry and, in 1953, Professor at Birkbeck College. In 1955 he became Regius Professor of Chemistry at the University of Glasgow, in 1957 he was appointed Professor of Organic Chemistry at Imperial College.

In 1950, Professor Barton showed that organic molecules could be assigned a preferred conformation based upon results accumulated by chemical physicists, in particular by Odd Hassel. Using this new technique of "conformational analysis", he later determined the geometry of many other natural product molecules.

In 1958 Prof. Barton was Arthur D. Little Visiting Professor at Massachusetts Institute of Technology, and in 1959 Karl Folkers Visiting Professor at the Universities of Illinois and Wisconsin.

In 1954 he was elected to Fellowship of the Royal Society, in 1956 he became Fellow of the Royal Society of Edinburgh; in 1965 he was appointed member of the Council for Scientific Policy . He was knighted in 1972 but chose to be known as Sir Derek only in Britain. In 1978 he became Director of the Natural Products Institute in France.

As well as for his work on conformation, his name is remembered in a number of reactions in organic chemistry.

He married three times, and had a son by his first marriage. He died 16 March 1998.