[reaction: see text] Iridium(III) hydrides prove to be air-stable active catalysts for intramolecular hydroalkoxylation and hydroamination of internal alkynes with proximate nucleophiles. The cyclization follows highly selective 6-endo-dig regiochemistry when regioselectivity is an issue.

The functionalized alkynes o-RCtC(C 6 H 4 )NO 2 (R ) H or alkyl) formally insert into two iridium hydrides, during which O-transfer of the nitro group into the CtC bond of o-RCt C(C 6 H 4 )NO 2 is observed. For the terminal alkyne with R ) H, iridium(III) nitroso complexes were isolated. For internal alkynes with R ) Me or n Pr, iridium hydride anthranil complexes were obtained as a result of O-transfer with a different regiochemistry. Mechanisms for these transformations, including a previously unknown O-transfer step from the nitro to the RCtC bond, are proposed.

Insertion of a variety of alkynes into the Ir−H bond of trans-[IrH(PPh3)2(C(Ph)CHC(O)Me)(acetone)]+ (1) follows three different routes depending on the alkyne structures. For relatively electron-rich alkynes (PhC⋮CH, PhCH2C⋮CH, and p-OMeC6H4C⋮CH), double insertion occurs stepwise, each alkyne undergoing rearrangement to a vinylidene intermediate independently to afford an iridium(III) η2-butadienyl. In the first alkyne insertion, deuterium labeling and crossover experiments confirm that the alkyne to vinylidene rearrangement is intraligand. Both a vinyl and a vinylidene intermediate were trapped and isolated during this first insertion. In the second alkyne insertion, a C−H agostic intermediate was isolated. Electron-poor alkynes (p-CF3C6H4C⋮CH and p-NO2C6H4C⋮CH) also undergo double insertion into 1, but deuterium labeling experiments using p-CF3C6H4C⋮CD indicate reversible C(sp)−H oxidative addition. Insertion of highly polarized alkynes [R1C⋮CC(O)R2] to 1 occurs only once and involves no vinylidene intermediates even when R1 = H. The regio- and stereochemistry in this case are mainly controlled by the steric effects of R1. In this series, rare cis-(PPh3)2 intermediates were isolated for HC⋮CC(O)R (R = Me or OMe). X-ray crystal structures of representative products are reported.

Tobacco bio-oil, gases, and char were produced through pyrolysis of tobacco leaves using a fluidized bed pilot plant under varying temperature (350, 400, 450, 500, 550, and 600 °C) and residence time (5, 10, and 17 s) conditions. The optimized condition for the production of bio-oil was found to be at 500 °C at a vapor residence time of 5 s, giving a bio-oil yield of 43.4%. The Colorado Potato Beetle (CPB) Leptinotarsa decemlineata L. (Coleoptera: Chrysomelidae), a destructive pest toward potato crops, and three microorganisms (Streptomyces scabies, Clavibacter michiganensis, and Pythium ultimum), all problematic in Canadian agriculture, were strongly affected by tobacco bio-oil generated at all pyrolysis temperatures. Nicotine-free fractions of the tobacco bio-oil were prepared through liquid−liquid extraction, and high mortality rates for the CPB and inhibited growth for the microorganisms were still observed. A potential pesticide from tobacco bio-oil adds value to the biomass as well as the pyrolysis process.

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