Premium
Synthesis of Dihydroisobenzofurans via Palladium‐Catalyzed Sequential Alkynylation/Annulation of 2‐Bromobenzyl and 2‐Chlorobenzyl Alcohols under Microwave Irradiation
Author(s) -
Buxaderas Eduardo,
Alonso Diego A.,
Nájera Carmen
Publication year - 2014
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201400457
Subject(s) - chemistry , catalysis , palladium , sonogashira coupling , annulation , reagent , potassium hydroxide , ligand (biochemistry) , propargyl , hydroxide , oxime , organic chemistry , combinatorial chemistry , biochemistry , receptor
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).