Synthesis of substituted furans by palladium-catalyzed cyclization of acetylenic ketones
摘要:
Palladium-catalyzed cyclization of beta,gamma-acetylenic ketones gives furans by intramolecular oxypalladation and subsequent protodemetalation. 3-Allylfurans were exclusively obtained by trapping the intermediate 3-furyl-palladium species with allyl halides in the presence of 2,2-dimethyloxirane as a proton scavenger.
Alkynones react with arylboronic acids in the presence of a rhodium(I) catalyst to afford four- and five-membered-ring cyclic alcohols equipped with a tetrasubstituted exocyclic olefin. The cyclic allylic alcohol skeleton is constructed by the carbon-carbon bond formation between the carbonyl group and an alkenylrhodium(I) intermediate formed by the regioselective addition of an arylrhodium(I) species across the carbon-carbon triple bond. (c) 2007 Elsevier Ltd. All rights reserved.
SAHA, MANASI;NICHOLAS, K. M., ISRAEL J. CHEM., 1984, 24, N 2, 105-107