Synthesis of Dihydroisobenzofurans via Palladium-catalyzed Sequential Alkynylation/Annulation of Aryl Bromides and Aryl Chlories under Microwave Irradiation

EDUARDO BUXADERAS; DIEGO A. ALONSO; CARMEN NÁJERA

ADVANCED SYNTHESIS & CATALYSIS (PRINT)

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2014 vol. 356 p. 3415 - 3421

1615-4150

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 120 ºC under microwave irradiation. 4,4´-Dichlorobenzophenone oxime derived chloro-bridged palladacycle 1a is an efficient precatalyst to perform this tandem process using XPhos as ancillary ligand and KOH as base in the absence of 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).