Ruthenium Supported Ionic Liquid Based PMO as an Efficient Heterogeneous Catalyst for sp ³ C─H Bond Alkylation of 9H ‐Fluorene With Primary Alcohols

Substituted monoalkylated fluorene derivatives are mainly found in pharmaceuticals, polymerization synthesis, plastics, and dye industries. Therefore, synthesis of monoalkylated fluorene derivatives is highly significant and desirable. In this work, periodic mesoporous organo‐silica(PMO) has been functionalized by ionic liquid 1‐methyl‐3‐(trimethoxysilylpropyl) imidazolium chloride by utilizing the alkoxy groups (‐OR) located in the pore wall of PMO, which assists in the effective stabilization of Ru supported over PMO‐IL. The textural, structural, and morphological properties of the catalyst was studied by various analytical techniques such as XRD, BET, TGA, FTIR, 29 Si(CP‐MAS), 13 C(CP‐MAS)‐NMR, XPS, ICP‐OES, FE‐SEM, and HR‐TEM. In this study, we present a green and efficient protocol for the synthesis of monoalkylated derivatives via sp 3 C‐H bond functionalization of 9H ‐fluorene with primary alcohol by adopting the borrowing hydrogen strategy, thereby excluding the use of toxic alkyl halides. The reaction was catalyzed by minimal loading of Ru@PMO‐IL (2.5 wt%), without the requirement of any ligands and external hydrogen source. The resulting catalyst showed excellent catalytic activity, high turnover number (TON), along with a wide range of substrate scope, which includes substituted primary alcohols and substituted 9H ‐fluorene derivatives, affording the corresponding alkylated products in good to excellent yields. Further, the catalyst was recycled for five catalytic cycles and showed insignificant loss in catalytic activity.