Synthesis of tetrahydrofuran homologs and acyclic 1,7-diketones

Conclusions

• 1. Condensation of furfural and 5-methylfurfural with aliphatic aldehydes and ketones and the substitution addition reaction toα-methylfuran yielded a series of furan saturated and unsaturated oxo compounds.

• 2. Hydrogenation of the latter in the liquid phase over Raney Cu-Al catalyst yielded the furan alcohols, 1-furyl-3-alkanols and 1-(5-methylfuryl)-3-alkanols, which upon hydrogenation by a flow-type method over Pt/C catalyst at 220° were transformed in a yield of 80% into 2,3-, 2,4-, and 2,5-dialkyltetrahydro-furans and 2,3,5-trialkyl- and 2,3,3,5-tetraalkyltetrahydrofurans.

• 3. Upon hydrogenation over a Pt/C catalyst at 220° 1-(5-methylfuryl)-3-alkanols having a secondary hydroxyl group form 1,7-diketones in a yield of ∼15%, in addition to tetrahydrofuran homologs.