Graphitic Carbon Nitride‐Supported Manganese Catalyst for Direct C(sp 3 )–H Alkylation of 9 H ‐Fluorene Using Alcohols

We demonstrated the C(sp 3 )–H alkylation of 9 H ‐fluorene with alcohols through a borrowing hydrogen mechanism, employing a graphitic carbon nitride‐supported manganese oxide heterogeneous catalyst. This cost‐effective manganese catalyst exhibits high reactivity and good functional‐group tolerance, selectively producing monoalkylated fluorene in high yields. Additionally, the catalyst is air‐stable, versatile across a wide range of substrates, suitable for gram‐scale synthesis, and can be recycled multiple times.