Mild halogenation of stabilized ester enolates by cupric halides
摘要:
The reactions of various stabilized ester enolates of 2-keto, 2-(alkoxycarbonyl), 2-phosphoryl, and 2-(benzenesulfonyl) esters with cupric chloride or cupric bromide have been examined. The reactions lead to 2-halo esters in good to excellent yields under mild condition. Enolates which contain an unsaturated functionality such as a double bond, a triple bond, or an allylic or a benzylic moiety react with high chemoselectivity.
addition/cyclization/halogen atomtransferbetween alkynes and α-halogeno-γ, δ-unsaturated carbonyl compounds for the synthesis of various substituted cyclopentenes is described. Since up to four Csp3–Csp2 bonds, two Csp3–Br bonds, and two carbocycles can be established in a single reaction, this 100% atom-efficient reaction exhibits the advantages of wide substrate scope, high functional group tolerance, and step-economics