Allene derivatives carbon-palladium formation

By using the same catalytic system, alkylations of 1,3-dimethylbarbituric acid with alcohols were also accomplished (Scheme 5.31) [68]. The Cp lr-catalyzed alkylation using 2-iodobenzyl alcohol, followed by palladium-catalyzed carbon-carbon bond formation with allene, gave spirocyclic barbituric acid derivatives in a one-pot process. 

The Larock method for annulation between vicinal iodo-arylamines and 1,2-dienes in the preparation of indoles can be adapted for preparation of azaindoles using corresponding azine substrates. Thus, substituted-3 f-pyrrolo[2,3-fc]pyridin-3-ones can be prepared from 2-amino-3-iodopyridine derivatives by a palladium carboannulation process with al-lenic compounds (Scheme 104). The bicyclic products, the methylene derivatives 308, and the alkylidenes 309 can be oxidatively cleaved with ketone formation. The reaction may proceed by formation of a pyridinylpalladium complex followed by the 7r-allyl complexa-tion of allenic derivatives 310. Since the polar substituents on terminal carbons of the rr-allyl system influence the regiochemistry of the reactions, nucleophilic attack of the nitrogen atom on the most electron-deficient carbon atom of the rr-allyl system affords either of the... 

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