Synthesis and reactivity of iron carbonyl complexes of β-silyl substituted α,β-unsaturated ketones

Abstract

β-Silyl α,β-unsaturated ketones, R₃SiCHCHC(O)Me (R₃Si = Me₃Si, Bu^tMe₂Si, PhMe₂Si), react with [Fe₂(CO)₉] at 35 °C in diethyl ether to give tetracarbonyl[R₃SiCHCHC(O)Me]iron(0) complexes and at 55 °C in toluene to give tricarbonyl[R₃SiCHCHC(O)Me]iron(0) complexes. Tricarbonyl[Me₃SiCHCHC(O)Me]iron(0) and tricarbonyl[Bu^tMe₂SiCHCHC(O)Me]iron(0) react with methyllithium under a nitrogen atmosphere to give hexane-2,5-dione and 3-(tert-butyldimethylsilyl)hexane-2,5-dione, respectively, and with methyllithium under a carbon monoxide atmosphere to give the vinylketene complexes tricarbonyl(3-methyl-5-trimethylsilyl-1-oxa-1,2,4-triene)iron(0) and tricarbonyl(5-tert-butyldimethylsilyl-3-methyl-1-oxapenta-1,2,4-triene)iron(0) respectively.