Palladium-catalyzed sequential oxidative cyclization/coupling of 2-alkynylphenols and alkenes: a direct entry into 3-alkenylbenzofurans.
A new Pd-catalyzed tandem intramolecular oxypalladation/Heck-type coupling between 2-alkynylphenols and alkenes is reported, leading to 3-(1-alkenyl)benzofurans. Participating alkenes include those substituted with an electron-withdrawing group (ester, ketone, amide, nitrile, sulfone), as well as styrene. Remarkably, beta-substituted-alpha,beta-unsaturated carbonyl-type derivatives also participate effectively. The ready availability of substituted alkynylphenols, together with flexibility in the alkene choice, makes this simple strategy a versatile one for the synthesis of structurally diverse benzofuran derivatives.
Martínez
Claudio
C
Departamento de Química Orgánica, Facultad de Química, Universidade de Vigo, Lagoas-Marcosende s/n, 36310 Vigo, Spain.
Alvarez
Rosana
R
Aurrecoechea
José M
JM
D000475:Alkenes / Q000138:chemical synthesis / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D001572:Benzofurans / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*
D000475:Alkenes; D000480:Alkynes; D001572:Benzofurans; D010636:Phenols; D010165:Palladium