Tandem Diels–Alder Cycloaddition/Aromatization of Biomass‐Derived 2‐Methylfuran Toward Renewable N,N‐ Diethyl‐3‐Methylbenzamide

Biomass holds significant promise as a sustainable feedstock for replacing petrochemical products in green chemical synthesis. Among biomass‐derived molecules, furan serves as a key building block for constructing diverse, high‐value bioactive molecules. Herein, this study presents a highly chemoselective and regioselective Diels–Alder (D‐A) reaction between biomass‐derived monosubstituted furans and acrylamides, followed by aromatization, enabling the efficient synthesis of the bioactive molecule N , N‐ Diethyl‐3‐methylbenzamide (DEET) with excellent selectivity. Notably, the catalyst (Hf(OTf) 4 ) serves not only as the Lewis acid center but also as a conformation‐directing template and intermediate stabilizer in this reaction. Gram‐scale syntheses were performed in both tubular and continuous‐flow reactors, confirming the scalability of this process. This methodology offers broad applicability for the regioselective synthesis of multisubstituted aromatic products from biomass‐derived furans, providing a novel approach for the high‐value conversion of biomass into bioactive molecules.