Palladium-catalyzed sequential alkylation-alkenylation reactions. Application to the synthesis of 2-substituted-4-benzoxepines and 2,5-disubstituted-4-benzoxepines.
The synthesis of 2-substituted-4-benzoxepines and 2,5-disubstituted-4-benzoxepines from aryl iodides and bromoenoates is described. This methodology is based on a palladium-catalyzed aromatic substitution followed by an intramolecular Heck sequence. Under the reaction conditions (Pd(OAc)(2) (10 mol %), tri-2-furylphosphine (20 mol %), norbornene (2 equiv), Cs(2)CO(3) (2 equiv), CH(3)CN, 85 degrees C), moderate to excellent yields of benzoxepines bearing numerous substituents (Me, F, Cl, etc.) are obtained.
Lautens
Mark
M
Davenport Laboratories, Chemistry Department, University of Toronto, Toronto, Ontario, Canada M5S 3H6. mlautens@chem.utoronto.ca
Paquin
Jean-François
JF
Piguel
Sandrine
S