Asymmetric 1,3-Dipolar Cycloaddition Reactions

A review of anti-infective and anti-inflammatory chalcones.

The review examines the chiral amine literature from 2000-2009 (May) concerning enantioselective and diastereoselective methods for N-acylenamide and enamine reduction, reductive amination, and imine reduction. The reaction steps for each strategy, from ketone to primary chiral amine, are clearly defined, with best methods and yields for starting material preparation and final deprotection noted. Categories of chiral amines have been defined in Section 1 to allow the reader to quickly understand whether their specific target amine falls within a difficult to synthesize, or not, structural class. Amino acids are not considered in this work.

Chiral Amine Synthesis – Recent Developments and Trends for Enamide Reduction, Reductive Amination, and Imine Reduction

Synthesis of piperidines

Index-Flowering plants; antifungal agents; constitutive compounds; phytoalexins; second- ary metabolites. Abstract-Recent work on the characterization of antifungal metabolites in higher plants is reviewed. Interesting new structures are discussed and the distribution of those substances in different plant families is outlined. Distinction is made between constitutive antifungal agents and phytoalexins, which are specifically formed in response to fungal inoculation. The literature survey covers the 12 years since 1982. INTRODUCTION A fungal spore landing on the leaf surface of a plant has to combat a complex series of defensive barriers set up by the plant before it can germinate, grow into the plant tissues and survive. The arsenal of weapons against the fungus includes physical barriers (e.g. a thick cuticle) and chemical ones, i.e. the presence or accumulation of anti- fungal metabolites. These can be preformed in the plant, the so called ‘constitutive antifungal substances’, or they are induced after infection involving de

Review article no. 92 a survey of antifungal compounds from higher plants, 1982-1993

Ulosantoin (2), a phosphorylated hydantoin, has been isolated from organic soluble extracts of the sponge Ulosa ruetzleri and found to exhibit marked insecticidal activity against tobacco hornworm larvae and cockroaches. The structure was determined by X-ray diffraction analysis. A structurally related compound, dimethyl N 2 -creatininylphosphate (1), was also isolated from the sponge extracts, but was inactive in the insecticidal screens

Ulosantoin, a potent insecticide from the sponge Ulosa ruetzleri

The first syntheses of the dendrobatid indolizidine alkaloids 167B (3), 205A (4), and 270A (5) are described using as a key step the highly stereoselective intramolecular nitrone cycloaddition of the (Z)-N-alkenylnitrone 10 to prepare the isoxazolidine 11. Mesylate-promoted cyclization of the alcohol 12, followed by reductive cleavage of the resulting mesylate salt, afforded the key axial hydroxymethyl compound 13, which was epimerized via tha aldehyde to the equatorial alcohol, and was subsequently reduced to the required 8-methyl-substituted indolizidine. The feasibility of extending this strategy to the enantioselective synthesis of such alkaloids was demonstrated in the first synthesis of (−)-indolizidine 209B (6), whose nitrone precursor 10d was obtained from the (S)-glutamate-derived amine 40

Colin Swithenbank

Papers

Ulosantoin, a potent insecticide from the sponge Ulosa ruetzleri

Stereoselective synthesis of (.+-.)-indolizidines 167B, 205A, and 207A. Enantioselective synthesis of (-)-indolizidine 209B

Stereoselective synthesis of (.+-.)-indolizidines 167B, 205A, and 207A. Enantioselective synthesis of (-)-indolizidine 209B

3′-formyl-2′,4′,6′-trihydroxydihydrochalcone from Psidium acutangulum

Highly Strained Bicyclic Systems. X.1-3 The Chemistry of 6-Substituted exo-5-Chlorobicyclo[2.1.1]hexanes