Iron-Catalyzed Acceptorless Dehydrogenative Coupling of Alcohols With Aromatic Diamines: Selective Synthesis of 1,2-Disubstituted Benzimidazoles

Ramachandra Reddy Putta; Simin Chun; Seok Beom Lee; Dong-Chan Oh; Suckchang Hong

doi:10.3389/fchem.2020.00429

Iron-Catalyzed Acceptorless Dehydrogenative Coupling of Alcohols With Aromatic Diamines: Selective Synthesis of 1,2-Disubstituted Benzimidazoles

Front Chem. 2020 Jun 19:8:429. doi: 10.3389/fchem.2020.00429. eCollection 2020.

Authors

Ramachandra Reddy Putta¹, Simin Chun^{1

2}, Seok Beom Lee^{1

2}, Dong-Chan Oh^{1

3}, Suckchang Hong^{1

2}

Affiliations

¹ BK21 PLUS Project, College of Pharmacy, Seoul National University, Seoul, South Korea.
² Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, South Korea.
³ Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul, South Korea.

Abstract

Benzimidazoles are important N-heteroaromatic compounds with various biological activities and pharmacological applications. Herein, we present the first iron-catalyzed selective synthesis of 1,2-disubstituted benzimidazoles via acceptorless dehydrogenative coupling of primary alcohols with aromatic diamines. The tricarbonyl (η⁴-cyclopentadienone) iron complex catalyzed dehydrogenative cyclization, releasing water and hydrogen gas as by-products. The earth abundance and low toxicity of iron metal enable the provision of an eco-friendly and efficient catalytic method for the synthesis of benzimidazoles.

Keywords: alcohol; benzimidazoles; borrowing hydrogen; dehydrogenative coupling; iron catalysis.