Five-Component [2 + 2 + 1 + 1] Tandem Benzannulation Leading to Multifunctionalized Aromatic Amines

Area of Science:

• Organic Chemistry
• Synthetic Methodology
• Heterocyclic Chemistry

Background:

• Aromatic amines are crucial building blocks in pharmaceuticals and materials science.
• Efficient synthesis of highly substituted aromatic amines remains a challenge.
• Multicomponent reactions offer atom economy and step efficiency for complex molecule synthesis.

Purpose of the Study:

• To develop a novel, regioselective five-component benzannulation strategy.
• To synthesize densely functionalized aromatic amines in a single operation.
• To explore a three-component cycloaddition for pyridine derivative synthesis.

Main Methods:

• A five-component [2 + 2 + 1 + 1] benzannulation reaction.
• Utilizing ynals, malononitriles, and sodium sulfinates as starting materials.
• A three-component [3 + 2 + 1] cycloaddition with ammonium thiocyanate (NH4SCN) as an ammonia surrogate.

Main Results:

• Established a regioselective benzannulation for synthesizing multifunctional aromatic primary amines.
• Achieved moderate to good yields of diverse aromatic amine products.
• Successfully synthesized 2-aminopyridine derivatives via a three-component cycloaddition.

Conclusions:

• The developed benzannulation strategy provides an efficient route to highly substituted aromatic amines.
• The method allows for the rapid assembly of complex molecular architectures.
• The three-component cycloaddition offers a valuable alternative for pyridine derivative synthesis.