benzofurans and 3-deoxyisoochracinic-acid

A simple and practical exo-oxime ether auxilixary for ortho-C-H functionalization of aromatic alcohols has been developed. Selective olefination of aromatic alcohols were first achieved via a six- or seven-membered exo-acetone oxime ether palladacycle with broad substrate scope. In addition, the crystal of the exo-palladacycle intermediate was obtained for the first time, and the application of this method in total synthesis of 3-deoxyisoochracinic acid was accomplished via a novel retro-synthetic disconnection approach, thus demonstrating the utility of this transformation.

Topics: Acetone; Alcohols; Benzofurans; Ethers; Hydrogen Bonding; Molecular Structure; Organometallic Compounds; Oximes; Palladium

In this study we used sequential catalysis-PPh(3)--catalyzed nucleophilic addition followed by Pd(0)-catalyzed Heck cyclization--to construct complex functionalized alkylidene phthalans rapidly, in high yields, and with good stereoselectivities (E/Z ratios of up to 1:22). The scope of this Michael-Heck reaction includes substrates bearing various substituents around the alkylidene phthalan backbone. Applying this efficient sequential catalysis, we accomplished concise total syntheses of 3-deoxyisoochacinic acid, isoochracinic acid, and isoochracinol.

Topics: Benzofurans; Catalysis; Molecular Structure; Palladium; Phosphines; Phthalic Acids; Stereoisomerism