30860-08-3

Upstream product

• 61732-72-7 meso-1,2-dibromo-1,2-di(4-methoxyphenyl)-2-ethane 
• 2132-64-1 2,2-bis-(p-methoxyphenyl)-1-bromoethylene 
• 4705-34-4 1,2-bis(4-methoxyphenyl)ethene 
• 2132-62-9 4,4'-dimethoxydiphenylacetylene 
• 2510-75-0 cis-4,4'-dimethoxystilbene 

Relevant academic research and scientific papers

Iridium-Catalyzed Hydrochlorination and Hydrobromination of Alkynes by Shuttle Catalysis

Described herein are two different methods for the synthesis of vinyl halides by a shuttle catalysis based iridium-catalyzed transfer hydrohalogenation of unactivated alkynes. The use of 4-chlorobutan-2-one or tert-butyl halide as donors of hydrogen halides allows this transformation in the absence of corrosive reagents, such as hydrogen halides or acid chlorides, thus largely improving the functional-group tolerance and safety profile of these reactions compared to the state-of-the-art. This method has granted access to alkenyl halide compounds containing acid-sensitive groups, such as tertiary alcohols, silyl ethers, and acetals. The synthetic value of those methodologies has been demonstrated by gram-scale synthesis where low catalyst loading was achieved.

Photolysis of 1-Bromo-2,2-bis(p-methoxyphenyl)ethene in solution

UV irradiation (λinc = 254 nm) of 1-bromo-2,2-bis(p-methoxyphenyl)ethene (AAHVB) in acetonitrile solution results in its decomposition: Φ(-AAHVB) = 0.18 both in the absence and presence of O2.Apart from the isomers the main photoproducts are 1,2-bis(p-methoxyphenyl)ethine (P-2) and HBr (Φ ca. 0.1).Flash photolysis studies in acetonitrile, dichloromethane and n-hexane solution at 266 nm revealed that P-2 is formed with a halflife of less than a few ns via a singlet route involving vinyl cations which rapidly rearrange and split off protons.Part of the vinyl cations decay via a differnet route forming an ionic species with an optical absorption band at ca. 350 nm.The decay of the latter is not correlated with the formation of P-2.This ionic species probably results from an interaction of vinyl cations with solvent or AAHVB.AAHVB quenches triplet states of various compounds X (e.g. benzophenone, chrysene, benzil, pyrene) provided that ET(X) >200 kJ mol-1.The energy transfer from these compounds to AAHVB does not result in the formation of P-2 or vinyl cations.

Elimination Reactions of Stilbene Dibromides. Dehydrobromination by Acetate, Cyanide or Chloride Ions in Dimethylformamide

Rates of dehydrobromination of a series of 4-nitro- and methoxystilbene dibromides by means of acetate, cyanide or chloride ions in dimethylformamide have been measured.A product analysis was performed which indicated a strong preference for anti elimination.Probable transition state structures utilized by each of the three nucleophiles are described.Attack by the base may be at either β-hydrogen (E 2H) or Cα(E2C).The slowest reaction in with chloride ion, which also gives the highest anti/syn elimination product ratio.