The telomerization reaction of 1,3-butadiene with alcohols to give alkyl octadienyl ethers in the presence of palladium-carbene catalysts has been studied in detail. Unprecedented catalyst efficiency with turnover numbers (TON) up to 1,500,000 and turnover frequencies (TOF) up to 100,000 h(-1) have been obtained after optimization for the reaction of methanol in the presence of an excess of in situ generated carbene ligands. High yields (75-97 %) and catalyst productivities (TON 15,000-100,000) are observed for other aliphatic alcohols and phenols. For comparison five carbene-palladium(0) complexes have been synthesized and characterized by X-ray crystallography. Both electronic and steric effects on the stability and reactivity of the catalysts have been discussed on the basis of density functional theory calculations.

SummarySynthetic methodologies have been developed which yield a variety of diphenylamine (DPA) and 1,3-diethyl-l,3-diphenylurea (ethylcentralite or EC) propellant stabiliser degradation derivatives in high yield. The N-alkyl nitroanilines 4,4, have been obtained either by reaction of the parent aniline with the required alkyl halide under mild conditions or via Ullmann type chemistry. A robust and high yielding approach for the synthesis of di, tri and tetranitrodiphenylamines (2,2 H ,4,4 H -tetranitrodiphenylamine; 2,4,4 H -trinitrodiphenylamine; 2,2 H ,4-trinitrodiphenylamine; 2,4,6-trinitrodiphenylamine; 2,4-dinitrodiphenylamine) is reported which involves passing the nitroanilines and chloronitrobenzenes down a base activated alumina column. The N-nitroso-N-alkyl compounds (N-nitroso-N-ethyl-4-nitroaniline; N-nitroso-N-ethyl-2-nitroaniline; N-nitroso-N-Methyl-4-nitroaniline; N-ethyl-N-nitrosoaniline; N-nitroso-2-nitrodiphenylamine) have been synthesised using nitrosyl acetate in acetic acid as the N-nitrosating agent.