A simple and efficient enantioselective synthesis of 2-alkylidene-3-alkyl-1,4-benzodioxanes by palladium-catalyzed annulation of benzene-1,2-diol and propargylic carbonates
[reaction: see text] Benzene-1,2-diol reacts with various propargylic carbonates in the presence of a palladium catalyst and a chiral atropoisomeric diphosphine to give 2-alkylidene-3-alkyl-1,4-benzodioxanes in good yields and 56-97% enantiomeric excess.
Labrosse
JR
Laboratoire de Synthese Asymetrique, associe au CNRS, CPE Lyon, Universite Claude Bernard Lyon, Villeurbanne, France.
Lhoste
P
Sinou
D