Robinson Annulation A Look Ahead to Synthesis

Conjugate, Michael, or 1,4-addition to an a,p-unsaturated carbonyl compound results in a saturated carbonyl compound, substituted at the p-position. 

Alcohols, thiols, amines, and cyanide can add both 1,2- and 1,4- to unsaturated carbonyl compounds, but since 1,2-addition is reversible, and 1,4-addition is not, only the 1,4-addition product is generally isolated. 

Related reactions can occur with other electron-poor alkenes, such as CH2=CHCN or CH2=CHN02. 

Epoxidation of electron-poor alkenes may be accomplished using the anion of hydrogen peroxide as a source of oxygen. 

While Grignard reagents generally add 1,2- to unsaturated aldehydes and ketones, in the presence of copper(l), or using an organocopper reagent, 1,4-addition occurs. 

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