Organic Lecture Series3Gilman ReagentsGilman reagents undergo conjugate additionto α,β-unsaturated aldehydes and ketonesin a reaction closely related to the Michael reaction:O1. ( CH3)2CuLi, ether, -78°C2. H2O, HClO3-Methyl-2-cyclohexenone3,3-Dimethyl-cyclohexanoneCH3CH3CH3Organic Lecture Series4Gilman ReagentsGilman reagents are unique among organometallic compounds in that they give almost exclusively 1,4-addition– other organometallic compounds, including Grignard reagents, add to the carbonyl carbon by 1,2-additionC H2C uLi2E t2O , -78oOC H3OC H31)2)H C l, H2O
Organic Lecture Series5organolithium and Grignard reagents, on the other hand, are strong nucleophiles (bases), add rapidly to carbonyl groups, and give primarily 1,2-addition:PhLiOO-Li+PhH2OHClOHPh4-Methyl-2-phenyl-3-penten-2-ol4-Methyl-3-penten-2-one+Phenyl-lithium1,2 Addition1,2 AdditionOrganic Lecture Series621234221,2 1,2 vsvs1,41,4-AdditionAddition
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