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Synthesis of Styrenes by Palladium(II)‐Catalyzed Vinylation of Arylboronic Acids and Aryltrifluoroborates by Using Vinyl Acetate
Author(s) -
Lindh Jonas,
Sävmarker Jonas,
Nilsson Peter,
Sjöberg Per J. R.,
Larhed Mats
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200802744
Subject(s) - palladium , vinyl acetate , chemistry , catalysis , organic chemistry , polymer chemistry , combinatorial chemistry , polymer , copolymer
One Heck of a reaction : Treatment of arylboronic acids or aryltrifluoroborates with vinyl acetate by using a palladium(II) catalyst gives the corresponding styrenes (see scheme). No palladium reoxidant is needed and the vinylation is performed under non‐inert conditionsReactions of aromatic and heteroaromatic boronic acids or aryltrifluoroborate salts with vinyl acetate in the presence of a palladium(II) catalyst give the corresponding styrenes in good yields. This Heck reaction proceeds with microwave heating in less than 30 min at 140 °C in the absence of base and tolerates a variety of substituents. No palladium reoxidant is needed and the vinylation is performed under non‐inert conditions. Mass spectrometry (electrospray ionization mass spectrometry (ESIMS) and tandem mass spectrometry (MS/MS)) was used to identify cationic palladium‐containing complexes in ongoing reactions. The key intermediates that have been detected, together with experiments that used deuterated vinyl acetate, support the existence of catalytically active palladium hydride species, and that it is the arylation of ethylene, not vinyl acetate, which generates the styrene product. The mechanism of the reaction is discussed in terms of the palladium(II) intermediates mentioned above.