Syntheses of γ-Lactones

γ-Lactones are very important flavor compounds.A series of γ-lactones,including γ-octanoic lactone and γ-nonanoic lactone and γ-undecanoic lactone,were synthesized by using cheap furfural and 1-bromopropane,1-bromobutane and 1-bromohexane as starting materials.The reactions of furfural with Grignard reagents of the bromoalkanes in ether gave 1-(2-furanyl) alkanols in c.a.86% yields.4-Oxocarboxylic acids were obtained in c.a.60% yields by the hydrolysis of 1-(2-furanyl) alkanols in w(HCl)=0.5% ethanol solution under reflux.4-Oxocarboxylic acids reacted with SOCl2 in methanol under reflux to give methyl 4-oxocarboxylates in c.a.93% yields.Methyl 4-oxocarboxylates were reduced with NaBH4 in methanol at room temperature,and cyclized concurrently to form γ-lactones in c.a.85% yields.