Cascade carbopalladation, intra-intermolecular reactions

Grigg and Xu have developed a variety of so-called queuing cascades involving allenes. The intra-intermolecular carbopalladation sequence of the <9-iodo-A-methyl-A -(methylallyl)aniline 142 and 1,1-dimethylallene 143 with subsequent / -dehydropalladation leads to the 1,3-dienyl-substituted indole derivative 144, which is immediately trapped by an added dienophile (e.g., A-methylmaleimide) in a Diels-Alder reaction to yield 145 (Scheme 37)7 ... 

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