Biography & contributions
Arthur Clay Cope [Arthur C. Cope], an American organic chemist born on June 27, 1909 – died on June 04, 1966. Cope is best known for the development of cope reactions, cope rearrangement reactions, rearrangement of allylic systems, discovering the change of 1,3,5 cyclooctatriene into bicyclo[4.2.0]-2,4-octadiene.
Cope also worked for projects like chemical warfare agents, antimalarial drugs, treatments for mustard gas poisoning.
Cope reaction
Cope reaction also termed as cope elimination reaction. It is an elimination reaction of the N-oxide of a tertiary amine to form an alkene and a hydroxylamine.
Mechanism
Cope reaction involves an intramolecular 5-membered cyclic transition state, leading to a syn elimination product. This organic reaction gives the same result as the Hofmann elimination, but the base is a part of the leaving group. The amine oxide is prepared by oxidation of the corresponding amine with an oxidant such as mCPBA. The actual elimination just requires heat.
Cope rearrangement
The Cope rearrangement is an organic reaction, involving conversion of 1,5-diene, to another 1,5-diene structural isomer. Cope rearrangement is belongs to a class of reactions termed "sigma tropic rearrangements". In this process bonds are forming and breaking at the same time. The main product is the thermodynamically more stable regioisomer.
The Oxy-Cope has a hydroxyl substituent on a sp3-hybridized carbon of the starting isomer. The driving force for the neutral or anionic Oxy-Cope Rearrangement is that the product is an enol or enolate (resp.), which can tautomerize to the corresponding carbonyl compound. This product will not equilibrate back to the other regioisomer. The Oxy-Cope Rearrangement proceeds at a much faster rate when the starting alcohol is deprotonated.
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