An efficient ultrasound-assisted zinc reduction of fatty esters containing conjugated enynol and conjugated enynone systems.
Reduction of methyl 8-hydroxy-11-E/Z-octadecen-9-ynoate (1) with zinc in either aqueous n-propanol or water under concomitant ultrasound irradiation furnished a mixture of methyl 8-hydroxy-9Z,11E-octadecadienoate (3a) and methyl 8-hydroxy-9Z,11Z-octadecadienoate (3b) (96% yield). Reduction of methyl 8-oxo-11-E/Z-octadecen-9-ynoate (2) under similar conditions gave methyl 8-oxo-10-Z-octadecenoate exclusively (4, 70%). The latter compound was epoxidized and converted to a C18 furanoid fatty ester (6, methyl 8,11-epoxy-8,10-octadecadienoate) in 70% yield.
Department of Chemistry, University of Hong Kong, Hong Kong. hrsclkj@hkucc.hku.hk
M S
MS
Lie Ken Jie
J
J
Mustafa
M K
MK
Pasha
D000480:Alkynes / Q000737:chemistry*; D001671:Biochemistry / Q000379:methods*; D005227:Fatty Acids / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D014463:Ultrasonography; D015032:Zinc / Q000737:chemistry*
D000480:Alkynes; D005227:Fatty Acids; C116186:methyl 8-hydroxy-11-octadecen-9-ynoate; D015032:Zinc