C₂-symmetric bisamidines: Chiral Brønsted bases catalysing the Diels- Alder reaction of anthrones

• Deniz Akalay,
• Gerd Dürner,
• Jan W. Bats and
• Michael W. Göbel

Beilstein J. Org. Chem. 2008, 4, No. 28, doi:10.3762/bjoc.4.28

• deprotonated by aqueous sodium hydroxide. As an “artefact” of the sequence rule, the S,S configurated diamine 9d leads to bisamidine ent-8d (Scheme 3). The anthrones 1b (R1: H; R2: Cl) and 1c (R1: Cl; R2: H) resulted from regioselective reductions of 1,8-dichloroanthraquinone [10][11]. Aliphatic side chains of

Combining two-directional synthesis and tandem reactions, part 11: second generation syntheses of (±)-hippodamine and (±)-epi-hippodamine

• Annabella F. Newton,
• Martin Rejzek,
• Marie-Lyne Alcaraz and
• Robert A. Stockman

Beilstein J. Org. Chem. 2008, 4, No. 4, doi:10.1186/1860-5397-4-4

• formally derivatives of perhydro-9b-azaphenalene (Figure 1). Another group of natural enemies, parasitic insects, can cause substantial reductions in populations of ladybird species. Recent research [2] has shown that the parasites locate the ladybirds through perception of certain defence alkaloids that

Part 1. Reduction of S-alkyl- thionocarbonates and related compounds in the presence of trialkylboranes/air

• Jean Boivin and
• Van Tai Nguyen

Beilstein J. Org. Chem. 2007, 3, No. 45, doi:10.1186/1860-5397-3-45

• % yield. No other identifiable product could be isolated. Zard and Nozaki mentioned similar reductions from α-acylxanthate[19] and α-acyliodide[20][21] respectively. These authors proposed the formation of an intermediate boron enolate that hydrolyses on work-up. A detailed report of our results

Contemporary organosilicon chemistry

• Steve Marsden

Beilstein J. Org. Chem. 2007, 3, No. 4, doi:10.1186/1860-5397-3-4

• -coupling reactions, and the use of silanes as stoichiometric reductants in a range of chemo-, stereo- and enantioselective catalytic reductions. It is therefore a pleasure to serve as Guest Editor for this first "Thematic Series" in the Beilstein Journal of Organic Chemistry, on "Contemporary Organosilicon

Multiple hydride reduction pathways in isoflavonoids

• Auli K. Salakka,
• Tuija H. Jokela and
• Kristiina Wähälä

Beilstein J. Org. Chem. 2006, 2, No. 16, doi:10.1186/1860-5397-2-16

• now reliably available in satisfactory or good yields by hydride reductions to be used as authentic reference compounds in analytical and biological studies. Background The reduction of isoflavones 1 has been actively studied during the last twenty years, owing to the range of interesting biological

• . The discussion is based on the types of reduced isoflavonoid structures formed (Figure 1), i.e., isoflavanones 2, cis-isoflavan-4-ols 3, trans-isoflavan-4-ols 4, the ring opened α-methyldeoxybenzoins 5 and 1,2-diaryl-2-propen-1-ols 6, and isoflavenes 7 and 8 (hydride reductions do not lead to

• cis- and trans-structures for the isoflavanol products and to study their conformational equilibria [32][34]. Borohydride reductions generally give a small preference for the cis products as suggested by Cram's rule [39]. We are not aware of any examples in the literature of single enantiomers of

Methods for the synthesis of polyhydroxylated piperidines by diastereoselective dihydroxylation: Exploitation in the two-directional synthesis of aza-C-linked disaccharide derivatives

• Andrew Kennedy,
• Adam Nelson and
• Alexis Perry

Beilstein J. Org. Chem. 2005, 1, No. 2, doi:10.1186/1860-5397-1-2

• Luche reduction of piperidinones Diastereoselective dihydroxylation of unsaturated piperidines Diagnostic nOe observations for the piperidine 22A Diagnostic nOe observations for the piperidines 22C and 22D Stereoselectivity of two-directional Luche reductions Two-directional functionalisation by