Total synthesis of diptoindonesin G and its analogues as selective modulators of estrogen receptors.

We have developed a versatile synthetic strategy for the synthesis of the natural product diptoindonesin G and its analogues as selective modulators of estrogen receptors. The strategy involves a regioselective dehydrative cyclization of arylacetals, a regioselective bromination of benzofurans, a sequential cross-coupling of bromo-benzofurans with aryl boronic acids, and a BBr3-mediated tandem cyclization and demethylation. Preliminary biological studies uncovered the critical and dispensable phenolic hydroxyl groups in the natural product and also revealed unexpected selectivity for isoforms of estrogen receptor.

Rhodium(I)-Catalyzed Benzannulation of Heteroaryl Propargylic Esters: Synthesis of Indoles and Related Heterocycles.

A de novo synthesis of a benzene ring allows for the preparation of a diverse range of heterocycles including indoles, benzofurans, benzothiophenes, carbazoles, and dibenzofurans from simple heteroaryl propargylic esters using a unified carbonylative benzannulation strategy. Multiple substituents can be easily introduced to the C4-C7 positions of indoles and related heterocycles.

A highly regio- and stereoselective synthesis of α-fluorinated imides via fluorination of chiral enamides.

A highly π-facial selective and regioselective fluorination of chiral enamides is described. The reaction involves an enantioselective fluorination exclusively at the electron-rich enamide olefin with N-F reagents such as Selectfluor and N-fluoro-benzenesulfonimide [NFSI] accompanied by trapping of the ß-fluoro-iminium cationic intermediate with water. The resulting N,O-hemiacetal could be oxidized using Dess-Martin periodinane, leading to an asymmetric sequence for syntheses of chiral α-fluoro-imides and optically enriched α-fluoro-ketones.

Protecting-group-free total synthesis of aplykurodinone-1.

A concise, stereoselective, and protecting-group-free total synthesis of aplykurodinone-1 from Hajos-Parrish ketone was described. The synthetic approach features a sequence of aerobic allylic oxidation and elimination of alcohol 9. The key intermediate for this synthesis was formed by a stereoselective intramolecular radical cyclization.

Tetra-µ-acetato-κO:O'-bis-{[2-(2-fur-yl)-1-(2-furylmeth-yl)-1H-benzimidazole-κN]copper(II)}.

The title complex, [Cu(2)(CH(3)COO)(4)(C(16)H(12)N(2)O(2))(2)], forms a dimer of the paddle-wheel type located on a crystallographic inversion centre. The two Cu(II) atoms [Cu⋯Cu = 2.7254 (11) Å] are bridged by four acetate anions. The geometry of the polyhedron around the metal centre can be described as tetra-gonal-pyramidal derived from the calculation of the value τ = 0.0018. The apical positions of the tetra-gonal-pyramidal copper coordination polyhedra are occupied by the N atoms of 2-(2-fur-yl)-1-(2-furylmeth-yl)-1H-benzimidazole ligands. In the crystal structure, mol-ecules are linked into a chain by inter-molecular C-H⋯O hydrogen bonds parallel to [010]. Two furan rings are disordered over two positions in ratios of 0.55:0.45 and 0.69:0.31.