Cross coupling/cycloaddition domino

Schemes Stepwise versus domino cross-coupling-cycloaddition reactions on 8-oxabi-cyclo [3.2. l]octa-2,6-dienes [22]...

Knoke and de Meijere [60] recently developed a highly flexible domino Heck-Diels-Alder reaction of a symmetrically substituted cumulene 125, which also involves cross-couplings of an allene at the central position. Both aryl and hetaryl halides react efficiently with l,3-dicyclopropyl-l,2-propadiene (125) and furnish 1,3,5-hexatriene derivatives 126 as intermediates, which are usually trapped by acceptor-substituted olefins in a subsequent cycloaddition, providing adducts 127a/b in moderate to good overall yields (Scheme 14.30). 

Scheme 14 A domino of twofold palladium-catalyzed allylation and reductive intramolecular cross-coupling reaction with subsequent cycloaddition [65]...

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