Sequential homobimetallic catalysis

On the other hand, an allyl ether can also be considered a protected alcohol that is liberated by Pd(0)-catalyzed allylation for further catalytic transformation. As an excellent example for sequential homobimetallic catalysis, Gabriele and coworkers [85] just recently disclosed a Pd(0)-catalyzed deprotection-Pd(II)-catalyzed heterocyclization of allyloxyaryl propargylic alcohols 97 to provide benzofurans 98 in excellent yields (Scheme 33). 

Gabriele et al. reported a sequential homobimetallic palladium-catalyzed cascade reaction for the synthesis of benzofuran derivatives 207 [80] (Scheme 6.57). Sequential homobimetallic catalysis is different in catalytic cycles promoted by the same metal but in different oxidation states. After oxidative addition and oxopalladation, 5-exo-dig cyclization occurs, followed by carbonylation, affording the intermediate 206. The allylic alcohol is reduced by H—Pd—I through formation of a ji-aUyl complex and the elimination of water. Finally, the product observed is afforded... 

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