Ethanol as H2 Source: Transfer Hydrogenation of Sulfur and Halogen Containing Nitroarenes with Anti-Poisoning Platinum on Carbon Catalyst

Abstract

Developing environmentally friendly transfer hydrogenation protocols using sustainable and economically viable hydrogen donors is highly desirable in the organic synthesis toolbox. In this respect, the high hydrogen content (13.1 wt%) and its low toxicity, including its production from renewable substances, make ethanol a promising hydrogen source. Herein, we report an attractive, recyclable, and, antipoisoning platinum on carbon (Pt/C) catalyst for the chemoselective reduction of functionalized nitroarenes comprising reactive functional groups, including multiple sulfur functionalities (-SO 2 Me, -SO 2 , SO 3 H, -SMe, etc.), halogens (-F, -Cl, -Br, -I) as well as carbonyl, amide, acid groups, selectively delivering structurally diverse aniline products in high yields (up to 95%) that are usually difficult to access. Therefore, the current approach may open up new possibilities for syntheses, especially with respect to chemical building blocks for drug development. The use of viable ethanol as a hydrogen source also makes this catalytic process sustainable.