Rh(III)-catalyzed synthesis of unsymmetrical acridines from aldehydes and azides using transient directing strategy in biomass-derived γ-valerolactone

ABSTRACT

An Rh(III)-catalyzed synthesis of unsymmetrical acridines from aldehydes and azides through bilateral cyclization process in biomass-derived γ-valerolactone has been developed. The in situ-generated imino directing group (DG) from aldehyde and catalytic amount of BnNH₂ worked as a transient directing group, thereby no additional steps were required for installation and removal of the DG. A series of functional groups were well tolerated, affording the desired products in good to excellent yields. Gram-scale synthesis of the product was also achieved.

GRAPHICAL ABSTRACT

KEYWORDS:

• C–H Activation
• green solvent
• transient directing groups
• unsymmetrical acridines

Additional information

Funding

We gratefully acknowledge the National Natural Science Foundation of China (21302014), the Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology (BM2012110), and the Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions the Advanced Catalysis and Green Manufacturing Collaborative Innovation Center of Changzhou University for the financial support.