Highly regioselective, sequential, and multiple palladium-catalyzed arylations of vinyl ethers carrying a coordinating auxiliary: An example of a Heck triarylation process

This article describes the development of new auxiliary-accelerated Heck mu ltiarylations by intramolecular presentation of the oxidative addition comp lex. The introduction of a specific, palladium-coordinating dimethylamino g roup allows for the desired chelation-accelerated and chelation-controlled triand diarylation reactions. We report (a) the first example of a Heck tri arylation process, (b) highly selective palladium-catalyzed diarylations of alkyl vinyl ethers, and (c) a very rapid two-phase protocol for the microw ave-assisted hydrolysis of amino-substituted, arylated vinyl ethers constit uting 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 function ality was rapidly (1-2 min) and efficiently released by microwave hydrolysi s after Heck multiarylation reactions. The liberated aromatic carbonyl comp ounds were thereafter isolated and fully characterized.