Buxaderas Pérez de Armiñán, Eduardo, Alonso, Diego A., Nájera, Carmen
Synthesis of Dihydroisobenzofurans via Palladium-Catalyzed Sequential Alkynylation/Annulation of 2-Bromobenzyl and 2-Chlorobenzyl Alcohols under Microwave Irradiation
Advanced Synthesis & Catalysis. 2014, 356(16): 3415-3421. doi:10.1002/adsc.201400457
URI: http://hdl.handle.net/10045/46006
DOI: 10.1002/adsc.201400457
ISSN: 1615-4150 (Print)
Abstract: 
The palladium-catalyzed synthesis of dihydroisobenzofurans has been performed by sequential Sonogashira cross-coupling/cyclization reactions between terminal alkynes and 2-(hydroxymethyl)bromo- and chlorobenzenes in methanol as solvent at 130 °C under microwave irradiation. A 4,4′-dichlorobenzophenone oxime-derived chloro-bridged palladacycle is an efficient pre-catalyst to perform this tandem process using 2-dicyclohexylphosphanyl-2′,4′,6′-triisopropylbiphenyl (Xphos) as ancillary ligand and potassium hydroxide as base in the absence of a copper cocatalyst. Under these conditions, functionalized 2-bromo- and 2-chlorobenzaldehydes are also suitable partners in the domino process affording phthalans in good yields. All the reactions can be performed under air and employing reagent-grade chemicals under low loading conditions (1 mol% Pd).
Keywords:Alkynes, Cycloisomerization, Dihydroisobenzofurans, Microwaves, Palladium, Sonogashira reaction
Wiley-VCH Verlag GmbH & Co. KGaA
info:eu-repo/semantics/article