orthometriseen

Ortho-metallation refers to a specific type of directed metallation reaction in organic chemistry. It is a process where a carbon-metal bond is formed at a position ortho to a directing group attached to an aromatic ring. This directing group, often containing heteroatoms like oxygen, nitrogen, or sulfur, plays a crucial role in coordinating with the metallating agent, such as an organolithium compound. This coordination directs the deprotonation and subsequent metallation to the adjacent ortho position, which is typically less acidic than other positions on the ring.

The regioselectivity of ortho-metallation is a key feature, allowing for precise functionalization of aromatic systems. Without a directing group, deprotonation of aromatic rings often occurs at the most acidic positions or in a less predictable manner. The presence of the directing group effectively "locks" the metallating agent in close proximity to the ortho carbon, facilitating its deprotonation. After the ortho-metal species is formed, it can undergo electrophilic attack, introducing a wide variety of substituents onto the aromatic ring at a specific location.

This reaction is highly versatile and has been employed in the synthesis of numerous complex organic molecules, including pharmaceuticals, natural products, and materials. The ability to selectively functionalize aromatic rings at the ortho position is a powerful tool for synthetic chemists, enabling the construction of molecules with tailored properties and functionalities. Common directing groups include methoxy, amide, carbamate, and phosphine oxide moieties. The choice of metallating agent and reaction conditions can also influence the efficiency and outcome of the ortho-metallation process.