Synthesis of Bio-Based Methylcyclopentadiene from 2,5-Hexanedione: A Sustainable Route to High Energy Density Jet Fuels

The sustainable, bio-based, platform chemical, 2,5-hexanedione [HD (1)], was efficiently converted to methylcyclopentadiene [MCPD (4)] through a three-step process consisting of intramolecular aldol condensation, catalytic chemoselective hydrogenation, and dehydration. Base-catalyzed aldol condensation of 1 resulted in the formation of 3-methyl-2-cyclopenten-1-one [MCO (2)], which was then converted to 3-methyl-2-cyclopenten-1-ol [MCP (3)] by chemoselective reduction with a ternary Ru catalyst system [RuCl2(PPh3)(3)/NH2(CH2)(2)NH2/KOH]. The hydrogenation proceeded with 96 % chemoselectivity. 3 was then dehydrated over AlPO4/MgSO4 at 70 degrees C under reduced pressure to yield 4, which can undergo an ambient temperature [4+2]-Diels-Alder cyclization to generate dimethyldicyclopentadiene (DMDCPD), a commodity chemical useful for the preparation of high-performance fuels and polymers. Through this approach, advanced jet fuels and materials can be conveniently produced from sustainable cellulosic feedstocks.

Automated summary

The sustainable, bio-based platform chemical 2,5-hexanedione was efficiently converted to methylcyclopentadiene through a three-step process involving intramolecular aldol condensation, catalytic chemoselective hydrogenation, and dehydration. This approach provides a new pathway for preparing high-performance fuels and polymers from sustainable feedstocks.