1 -Iodo-2,6-dimethoxybenzene

Similar para-quinone derivatives can be obtained by oxidative demethyla-tions of phenol ethers which can be performed in water. Either [bis(trifluo-roacetoxy)iodo]benzene 4 or the polymer-supported reagent 19 can be used for the generation of para-quinones 38 from 1,4-dimethoxybenzene derivatives of type 39, Scheme 19 [93]. 

Domino reactions of two molecules of l-iodo-2,3-dimethoxybenzene (134), in which the position for the second cyclopalladation is blocked, gave 135. The reaction proceeds via formation of the palladacycle 136. Oxidative addition of 134 to 136 generates 137. Reductive elimination of 137 gives 138. Then cyclopalladation of 138 and reductive elimination afford the ether ring 135. 

Intermolecular reaction of l-iodo-2,3-dimethoxybenzene (134) with the vinyl bromide 140 (10 equiv.) gave a mixture of 141 and 142 [37]. In this reaction, oxidative addition of 140 to the palladacycle 143 generates 144, and the coupled product 145 is formed by reductive elimination. Finally 5-exo cyclization of 145 and -H elimination afford 141. 

Tsuji reported a total synthesis of zearalenone using Pd-catalyzed carbonylation. In this total synthesis, they synthesized the key compound by Pd-catalyzed carbonylation. The reacion of l-iodo-2-phenylthiomethyl-4,6-dimethoxybenzene 3 (Scheme 7) with 10-iodo-6,2 -[l,3]dioxolane-2-decanol 4 was carried out under carbon monoxide (12 atm) to afford the corresponding m-iodoalkyl ester of 2-phenylthiomethy 1-4,6-dimethoxybenzene 5. 

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