Allylation and benzylation of p-quinones was achieved through an unusual redox chain reaction. Mechanistic studies suggest that the existence of trace hydroquinone initiates ar edoxc hain reaction that consists of aL ewis acid catalyzedF riedel-Crafts alkylation and as ubsequent redox equilibrium that regenerates hydroquinone.T he electrophiles could be various allylic and benzylic esters.T he addition of Hantzsche ster as an initiator improves the efficiency of the reaction.Quinone compounds participate in many naturally occurring electron-transfer processes owing to their unique redox properties. [1] Fore xamples,u biquinone (CoQ 10 )i sa sakey component of the aerobic cellular respiration process in most eukaryotic cells; [2] and plastoquinone and phylloquinone (Vitamin K) act as electron acceptors in photosynthesis in green leaves. [3] Many natural or synthetic quinone compounds thus exhibit potent biological activities as drug candidates for targeting relevant biochemical processes. [4] Thee lectronic properties of quinone derivatives have also attracted much attention from researchers working on functional materials. [5] Theb ulk of established chemical syntheses of quinones use af unctionalization-oxidation strategy.S ubstituents are first installed on hydroquinones,p henols,o rp henyl ethers through Friedel-Crafts reactions, [6] radical reactions, [7] and transition-metal-catalyzed coupling reactions, [8] and the resulting compounds are then oxidized to quinones. [9] Functionalized hydroquinone precursors can also be obtained through nucleophilic addition [10] and cycloaddition reaction [11] of simple quinones to substituted 2-cyclohexen-1,4-dione intermediates,w hich can then rearrange to hydroquinone and be oxidized. [12] Alternatively,L ipshutz [13] and Negishi [14] developed efficient syntheses of CoQ 10 based on metalcatalyzed cross-coupling between chloromethyl-CoQ 0 and organoaluminum or organozinc reagents.R ecently emerged direct quinone functionalization methods include radical CÀ Hf unctionalization with aryl boronic acids [15] and transitionmetal-catalyzed C À Hfunctionalization with broader varieties of coupling substituents. [16] However,benzylation of quinones remains challenging.H erein, we report am ild, one-step, redox-economical [17] catalytic allylation and benzylation of pquinones and the study of its unique mechanism, in which allyl and benzyl esters serve as the electrophiles and quinones are the formal "nucleophiles" (Scheme 1).