Blomquist cyclic ketone synthesis

What is Blomquist cyclic ketone synthesis?

Blomquist first reported the Blomquist cyclic ketone synthesis in 1947. This reaction enables the formation of intermediate to macrocyclic ketones by intramolecular condensation of aliphatic diketenes at diluted concentration.

Blomquist Cyclic Ketone Synthesis
Blomquist cyclic ketone synthesis

The resulting cyclic ketene derivatives are subsequently subjected to hydrolysis and decarboxylation. Intermolecular condensation of diketenes produces even larger macrocyclic diketones, which can be converted into simple macrocyclic diketones. Ketene can be easily obtained by treating acyl chloride of dicarboxylic acid with tertiary amines, with triethylamine giving the best result. While some polyketene products may form during the process, they can be readily removed. Other methods for preparing macrocyclic ketones include the Ziegler reaction, Hunsdiecker reaction, Ruzicka large ring synthesis, and Gliński reaction.

The Blomquist cyclic ketone synthesis is widely applicable in the production of intermediate to macrocyclic ketones, such as civetone and muscone.