benzofurans and phosphine

A phosphine-catalyzed (4 + 2) annulation of tetrahydrobenzofuranone-derived allenoates and benzofuran-derived azadienes (BDAs) has been achieved to construct the decahydro-2

Topics: Benzofurans; Catalysis; Phosphines; Stereoisomerism

An efficient organocatalytic asymmetric [3 + 2] cycloaddition reaction between 3-substituted methylenebenzofuranone derivatives and diverse Morita-Baylis-Hillman carbonates to provide complex polysubstituted spirocyclopentenebenzofuranone scaffolds in a single step is reported. C2-symmetric phospholanes were efficient nucleophilic catalysts of this transformation under mild conditions, providing reaction products comprised of three consecutive stereocenters, including one all-carbon center, with excellent enantioselectivity.

Topics: Benzofurans; Catalysis; Cycloaddition Reaction; Molecular Structure; Phosphines; Stereoisomerism

A regioselective [3 + 2] cycloaddition of benzofuranone type active olefins with allenoates catalyzed by trivalent phosphines has been developed, which provided an easy access to enriched functionalized spirocyclic benzofuranones. The reactions accommodated a number of benzofuranone type electron-deficient olefins and allenoates to give the desired 3-spirocyclopentane benzofuran-2-ones or 2-spirocyclopentane benzofuran-3-ones with moderate to excellent yields (up to 99%) and moderate to good regioselectivities (up to 11:1).

Topics: Alkenes; Benzofurans; Catalysis; Crystallography, X-Ray; Cyclization; Electrons; Ketones; Lewis Bases; Models, Molecular; Molecular Structure; Phosphines; Spiro Compounds

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

An efficient chiral phosphine-catalyzed asymmetric substitution reaction of MBH carbonates with 3-substituted benzofuran-2(3H)-ones or 3-substituted oxindoles has been described in this context, giving the corresponding allylic alkylation products bearing adjacent quaternary and tertiary stereogenic centers in high yields, moderate diastereoselectivities and high enantioselectivities under mild conditions.

Topics: Alkylation; Allyl Compounds; Benzofurans; Carbonates; Catalysis; Indoles; Oxindoles; Phosphines; Stereoisomerism

A novel phosphine-catalyzed domino reaction of salicyl N-thiophosphinyl imines and allylic carbonates was developed. The allylic carbonate, in this reaction, serves as a new kind of 1,1-dipolar synthon. This method offered a powerful approach to the construction of a highly substituted trans-2,3-dihydrobenzofuran skeleton with high diastereoselectivity.

Topics: Benzofurans; Carbonates; Catalysis; Imines; Molecular Structure; Phosphines; Salicylates; Stereoisomerism