3622-76-2Relevant articles and documents
Cannon,J.G. et al.
, p. 934 - 937 (1976)
Highly regioselective, sequential, and multiple palladium-catalyzed arylations of vinyl ethers carrying a coordinating auxiliary: An example of a heck triarylation process
Nilsson,Larhed,Hallberg
, p. 8217 - 8225 (2007/10/03)
This article describes the development of new auxiliary-accelerated Heck multiarylations by intramolecular presentation of the oxidative addition complex. The introduction of a specific, palladium-coordinating dimethylamino group allows for the desired chelation-accelerated and chelation-controlled tri- and diarylation reactions. We report (a) the first example of a Heck triarylation process, (b) highly selective palladium-catalyzed diarylations of alkyl vinyl ethers, and (c) a very rapid two-phase protocol for the microwave-assisted hydrolysis of amino-substituted, arylated vinyl ethers constituting an entry to diarylated ethanals and substituted desoxybenzoins. X-ray structures and product patterns support the suggested substrate-controlled Heck reaction pathway. The catalyst-directing alkyl dimethylamino functionality was rapidly (1-2 min) and efficiently released by microwave hydrolysis after Heck multiarylation reactions. The liberated aromatic carbonyl compounds were thereafter isolated and fully characterized.
Chelation-Controlled, Palladium-Catalyzed Vinylic Substitution Reactions of Vinyl Ethers. 2-Arylethanal Equivalents from Aryl Halides
Andersson, Carl-Magnus,Larsson, Joakim,Hallberg, Anders
, p. 5757 - 5761 (2007/10/02)
The regioselectivity of palladium-catalyzed arylation reactions of a series of nitrogen-containing vinyl ethers is reported.The presence of a β-amino substituent gives a profound influence on regiochemistry.Thus, the arylation of ethene (1c) with a variety of aryl iodides and bromides provides the β-arylation products ethenyl>arenes (3) with at least 95percent selectivity and in good yields.The corresponding arylation of butoxyethene is a nonselective process giving a mixture of α- and β-substitution products.The palladium-catalyzed arylation of 1c constitutes an entry to 2-arylethanals after cleavage of the enol ether.The directing effect of the amino group is discussed in terms of chelation with the intermediate arylpalladium halide.