Palladium-Catalyzed Tandem Cyclization/Suzuki Coupling Reaction of 1,2,7-Trienes

[reaction: see text] A Pd(0)-catalyzed 1,2,7-triene cyclization/arylation cascade reaction was realized via pi-allylpalladium intermediate formation and a subsequent Suzuki coupling reaction to preferentially give a five-membered ring product with a stereodefined exocyclic double bond. Excellent cis/trans selectivity was achieved (only cis-3 was isolated) with heteroatom-tethered 1,2,7-triene substrates.

Allenes as carbon nucleophiles in palladium-catalyzed reactions: observation of anti attack of allenes on (pi-allyl)palladium complexes

In the palladium-catalyzed cyclization of allenic allylic esters using Pd(dba)2 as catalyst, it was shown that the allene acts as a carbon nucleophile. Intermediates were isolated and stereochemical studies established that the double bond of the allene has attacked the (pi-allyl)palladium intermediate on the face opposite to that of palladium.