Two diastereoisomers of tetranuclear cyclometallated iridium complexes, either having an inner core of HEXOL-type [Ir(IrCl2)3]6+ unit and a surface of six chiral, didentate, cyclometallated ligands, are stereoselectively synthesized from an enantiopure pinenopyridine derivative.

α-Diaminoboryl carbanions, readily prepared from acetonitrile, stereoselectively convert 2-nitrobenzaldehydes into nitrophenyl (Z)-acrylonitriles. Subsequent reductive cyclization leads to a series of 2-aminoquinoline derivatives. The entire procedure is practically operated in a single flask.

Gregor Breckle, Kurt Polborn, and Thomas Lindel Ludwig-Maximilians-Universität München, Department of Chemistry, Butenandtstr. 5Ð13, D-81377 Munich, Germany Reprint requests to Prof. Dr. Th. Lindel. Fax int: +(0)89/2180-7-7734. E-mail: [email protected] Z. Naturforsch. 58b, 451Ð456 2003; received February 17, 2003 The marine pyrrole-imidazole alkaloid sventrin (1) and the hither...

methyl tetra - 0-methyl- ?-d- glucopyranoside is stereoselectively prepared from tetramethyl-d- glucopyranose by using (mei+nah) in toluene (86%) or cyclohexane (85%), while its ?- isomer is best synthesized in hexamethyl phosphoramide (64%). similarly, methyl tetra-o-methyl-?- d-mannopyranoside is synthesized in cyclohexane (80%), while its ?- isomer is predominantly prepared by (mei+n-buli) i...

Methyl tetra - 0-methyl- ?-D- glucopyranoside is stereoselectively prepared from tetramethyl-D- glucopyranose by using (MeI+NaH) in toluene (86%) or cyclohexane (85%), while its ?- isomer is best synthesized in hexamethyl phosphoramide (64%). Similarly, methyl tetra-o-methyl-?- D-mannopyranoside is synthesized in cyclohexane (80%), while its ?- isomer is predominantly prepared by (MeI+n-Bu...

Iodoarylation of arylacetylenes was performed using a simple reagent system composed of molecular iodine and [bis(benzoyloxy)iodo]benzene. Most arylacetylenes efficiently underwent the iodoarylation reaction with electron-rich arenes to give trans 1,1-diaryl-2-iodoethene adducts regio- and stereoselectively. As an exception, the iodoarylation of p-methoxyphenylacetylene resulted in a mixture of...

Bench-top-storable (Z)-enethiol reagents: gold (Z)-1-decenylthiolates were synthesized stereoselectively in high yields. They are stable upon storage at room temperature without protection from light, and react smoothly with various alkyl halides, α,β-unsaturated ketones, and electron-deficient aryl halides with excellent stereoselectivity.

A difluorinated dienophile underwent cycloaddition reactions with a range of furans to afford cycloadducts which could be processed regio- and stereoselectively via episulfonium ions, generated by the reaction between their alkenyl groups and phenylsulfenyl chloride. The oxabicyclic products were oxidised to the phenylsulfonyl level and ring opened via E1(C)B or reductive desulfonative pathways...

The first enantioselective total synthesis of (+)-stachyflin, a potential anti-influenza A virus agent, was achieved; the method features a BF(3).Et(2)O-induced domino epoxide-opening/rearrangement/cyclization reaction to stereoselectively form the requisite pentacyclic ring system in one step.

A macrodiolide antibiotic pamamycin-607 was synthesized by joining two hydroxy acid components. Three cis-2, 5-disubstituted tetrahydrofuran rings in the molecule were stereoselectively prepared by radical cyclization reactions of beta-alkoxyvinyl ketone intermediates and a beta-alkoxymethacrylate substrate. The key step of the synthesis is characterized by the predominant threo product formati...