49826-98-4

Silver complexes with 5-(4-(tert-butyl)-1H-imidazol-1-yl)-imidazo[1,5-a]pyridin-3-ylidene ligands were synthesized as metal-imidazole acid-base cooperative catalysts. Single crystal XRD analysis revealed that the silver atom was located in the vicinity of

A Pd/N-heterocyclic carbene-based catalyst achieves the Sonogashira coupling of an array of functionalized, β-hydrogen-containing alkyl bromides and iodides under mild conditions. By furnishing the first example of a nonphosphine-based palladium catalyst

In 1996, the exotic white-spotted tussock moth (WSTM), Orgyia thyellina (Lepidoptera: Lymantriidae), was discovered in Auckland, New Zealand. Because establishment of WSTM would threaten New Zealand's orchard industry and international trade, eradication of WSTM with microbial insecticide was initiated. To monitor and complement eradication of WSTM by capture of male moths in pheromone-baited traps, pheromone components of female WSTM needed to be identified. Coupled gas chromatographic-electroantennographic detection analysis of pheromone gland extract revealed several compounds that elicited responses from male moth antennae. Mass spectra of the two most EAD-active compounds suggested, and comparative GC-MS of authentic standards confirmed, that they were (Z)-6-heneicosen-11-one (Z6-11-one) and (Z)-6-heneicosen-9- one, the latter termed here 'thyellinone.' In field experiments in Japan, Z6- 11-one plus thyellinone at a 100:5 ratio attracted WSTM males, whereas either ketone alone failed to attract a single male moth. Addition of further candidate pheromone components did not enhance attractiveness of the binary blend. Through the 1997-1998 summer, 45,000 commercial trap lures baited with 2000 μg of Z6-11-one and 100 μg of thyellinone were deployed in Auckland towards eradication of the residual WSTM population.

Tetrabutylammonium borohydride hydroborates unsaturated systems in refluxing chloroform. With eneynes, selectivity is observed for terminal unsaturation. However, selectivity is not observed with dienes.

A multistage stereospecific synthesis of components of the natural pheromone was realized.Conditions were found for stereospecific trans-reduction of the triple bonds.A procedure was developed for regiospecific dehydrohalogenation of 1,2-dibromoalkanes.Conditions giving the Z and E isomers in ratio of 96 : 4 were found for the Wittig reaction.

Regio/Enantioselective synthesis of niphatesines A-D is achieved making use of Pd(0) assisted 3-alkylation of pyridine as the key step.Absolute configuration of niphatesines C and D is established.

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Efficient synthetic routes to gossyplure and its components (1a and 1b) were formulated.The three key units viz the alkynol 3, the bromide 5, and the alkanal 13 were derived from easily accessible starting materials.Alkylation of 3 with 5, and subsequent semihydrogenation followed by oxidation, provided the C11-alkenal 8 which was subjected to a stereocontrolled Wittig reaction with a C5-phosphonium salt, to yield directly the disired pheromone (1a + 1b).The synthesis of its individual components involved the manipulation via an acetylenic intermediate, viz the alkynol 14 which was obtained through alkylation of 3.A sequence of well-established reactions on 14, then provided the corresponding (E)- and (Z)-alkenylphosphonium salts which upon a (Z)-specific Wittig olefination with the C7-aldehyde (13), led to the stereoselective synthesis of 1a and 1b.

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