What are the reactants in a Corey-Fuchs reaction?

The reactants in a Corey-Fuchs reaction are an aldehyde and a mixture of carbon tetrabromide and triphenylphosphine.

In a Corey-Fuchs reaction, the primary reactants are an aldehyde and a mixture of carbon tetrabromide (CBr4) and triphenylphosphine (PPh3). This reaction is a two-step process that results in the formation of an alkene. The Corey-Fuchs reaction is named after the American chemists Elias James Corey and Philip L. Fuchs, who first reported it in 1972.

The first step of the Corey-Fuchs reaction involves the reaction of the aldehyde with carbon tetrabromide and triphenylphosphine. This results in the formation of a bromoalkyne intermediate. The aldehyde is converted into a dibromoolefin via the phosphonium ylide, which is formed by the reaction of the aldehyde with triphenylphosphine. The phosphonium ylide then reacts with carbon tetrabromide to form the dibromoolefin.

In the second step, the bromoalkyne intermediate is treated with a strong base, typically butyllithium (BuLi), to form the final alkene product. The base deprotonates the bromoalkyne, leading to the formation of a carbanion. This carbanion then undergoes an elimination reaction, resulting in the formation of the alkene.

The Corey-Fuchs reaction is a useful method for the synthesis of alkynes from aldehydes. It is particularly useful for the synthesis of terminal alkynes, which can be difficult to prepare using other methods. The reaction is also stereospecific, meaning that it produces a single stereoisomer of the alkene product. This makes the Corey-Fuchs reaction a valuable tool in the synthesis of complex organic molecules.