Rhodium-catalyzed anti-Markovnikov addition of secondary amines to arylacetylenes at room temperature

An efficient method for synthesis of E-enamines by the anti-Markovnikov addition of secondary amines to terminal alkynes is described. The reaction of a variety of aryl- and heteroarylacetylenes proceeded at room temperature using a combination of a 8-quinolinolato rhodium complex and P(p-MeOC(6)H(4))(3) as a catalyst. The products were obtained as enamines by simple bulb-to-bulb distillation.     

Ruthenium-catalyzed arylation of fluorinated aromatic ketones via ortho-selective carbon-fluorine bond cleavage

We report here ruthenium-catalyzed arylation of fluorinated aromatic ketones via ortho-selective carbon-fluorine bond cleavage. In the presence of trimethylvinylsilane and cesium fluoride, ortho carbon-fluoride bonds of aromatic ketones were phenylated by 5,5-dimethyl-2-phenyl-1,3,2-dioxaborinane using RuH₂(CO)(PPh₃)₃ as a catalyst. Tandem C-F phenylation/C-H alkylation was observed for substrates bearing both one ortho hydrogen and one ortho fluorine atoms.     

Charge‐transfer character of halogen bonding: Molecular structures and electronic spectroscopy of carbon tetrabromide and bromoform complexes with organic σ‐ and π‐donors

Carbon tetrabromide and bromoform are employed as prototypical electron acceptors to demonstrate the charge‐transfer nature of various intermolecular complexes with three different structural types of electron donors represented by (1) halide and pseudohalide anions, (2) aromatic (π‐bonding) hydrocarbons, and (3) aromatics with (n‐bonding) oxygen or nitrogen centers. UV–Vis spectroscopy identifies the electronic transition inherent to such [1:1] complexes; and their Mulliken correlation with the donor/acceptor strength verifies the relevant charge‐transfer character. X‐ray crystallography of CBr₄/HCBr₃ complexes with different types of donors establishes the principal structural features of halogen bonding. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:449–459, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20264