112654-21-4Relevant articles and documents
Catalytic amphiphilic allylation via bis-π-allylpalladium complexes and its application to the synthesis of medium-sized carbocycles
Nakamura,Aoyagi,Shim,Yamamoto
, p. 372 - 377 (2001)
The reaction of certain activated alkenes 3 with allyltributylstannane (4) and allyl chloride (5a) in the presence of palladium catalyst gave the bis-allylation products, 1,7-octadiene derivatives 6a-k, in good to high yields. The reaction of certain imin
Control of the regioselectivity in catalytic transformations involving amphiphilic bis-allylpalladium intermediates: Mechanism and synthetic applications
Solin,Narayan,Szabo
, p. 1686 - 1693 (2001)
Various dialkyl-substituted allyl Chloride derivatives (2d-i) undergo regioselective palladium-catalyzed coupling reactions with allylstannanes (1a,b) and benzylidenemalonitrile (4), providing functionalized 1,7-octadienes in good yield. The catalytic reaction proceeds through an unsymmetrical amphiphilic bis-allylpalladium intermediate. An introductory electrophilic attack on the terminal position of the unsubstituted allyl moiety is followed by a nucleophilic attack on the alkyl-substituted allyl ligand. A theoretical analysis was performed by applying density functional theory at the B3PW91/DZ+P level to study the substituent effects on the electrophilic attack. According to the theoretical results, the high regioselectivity can be ascribed to the electronic effects of the alkyl substituents: The terminal alkyl groups destabilize the η1,η3-bis-allylpalladium intermediate of the reaction; in addition, the alkyl substitution increases the activation, barrier for the electrophilic attack.
Catalytic reactions of bis-π-allylpalladium generated from allyltrifluoroborate
Nakamura, Hiroyuki,Shimizu, Kazuki
experimental part, p. 426 - 429 (2011/02/28)
Bis-π-allylpalladium-catalyzed nucleophilic allylations to aldehydes 2 and imines 3 have been achieved by replacing allylstannanes with allyltrifluoroborate. Amphiphilic bisallylation of activated olefins 6 with allyltrifluoroborate and allyl acetate also proceeded smoothly in the presence of Pd2(dba)3·CHCl3 and tricyclohexylphosphine catalysts.
Palladium-catalyzed electrophilic substitution of allyl chlorides and acetates via bis-allylpalladium intermediates
Wallner, Olov A.,Szabo, Kalman J.
, p. 2934 - 2943 (2007/10/03)
Palladium-catalyzed electrophilic allylic substitution of functionalized allyl chlorides and allyl acetates can be achieved in the presence of hexamethylditin under mild and neutral reaction conditions. This efficient one-pot procedure involves palladium-catalyzed formation of transient allylstannanes followed by generation of a bis-allylpalladium intermediate, which subsequently reacts with electrophiles. Using this catalytic transformation, various aldehydes and imines can be allylated providing highly functionalized homoallyl alcohols and amines. Furthermore, tandem bis-allylation reactions could be performed by employing tosyl isocyanate and benzylidenemalonitrile as substrates. A particularly interesting mechanistic feature of this reaction is that palladium catalyzes up to three different transformations in each catalytic cycle. Various allylic functionalities, including COOEt, CONH2, COCH3, CN, Ph, and CH3, are tolerated in the catalytic reactions due to the application of neutral and mild reaction conditions. The substitution reaction occurs with very high regioselectivity at the branched allylic terminus. Moreover, in several reactions, a high stereoselectivity was observed indicating that this new catalytic process has a high potential for stereoselective synthesis. The regioselectivity of the reaction can be explained on the basis of DFT calculations. These studies indicate that the allylic substituent prefers the γ-position of the η1-allyl moiety of the reaction intermediate.
