32383-98-5

Upstream product

• 555-16-8 4-nitrobenzaldehdye 
• 99-73-0 para-bromophenacyl bromide 
• 2039-82-9 1-bromo-4-ethenyl-benzene 
• 4209-02-3 1-(4-bromophenyl)-2-chloroethan-1-one 
• 19134-89-5 1-(4-bromophenyl)-3-(4-nitrophenyl)prop-2-en-1-one 
• 99-90-1 para-bromoacetophenone 

Downstream Products

• 91358-52-0 [3-(4-Bromo-phenyl)-2-chloro-1-(4-nitro-phenyl)-3-oxo-propyl]-thiocarbamic acid S-methyl ester 
• 91358-49-5 1-(4-Bromo-phenyl)-3-chloro-2-hydroxy-3-(4-nitro-phenyl)-propan-1-one 
• 91358-46-2 (4-Bromo-phenyl)-[(4S,5S)-2-methylsulfanyl-4-(4-nitro-phenyl)-4,5-dihydro-oxazol-5-yl]-methanone 

Relevant academic research and scientific papers

A new class of bifunctional chiral phase transfer catalysts for highly enantioselective asymmetric epoxidation of α,β-unsaturated ketones at ambient temperature

A new type of bis-quaternary ammonium bromide as chiral multifunctional phase transfer catalysts derived from readily available inexpensive cinchona alkaloids has been developed and evaluated for the enantioselective asymmetric epoxidation of various chalcones in the presence of lower concentrations of various oxidants, bases, solvents and ambient temperature conditions. Under optimized reaction conditions, highest chemical yields of up to 98% along with the excellent enantioselectivities of about 99% were obtained by using the cinchona based chiral multifunctional phase transfer catalysts.

N-Heterocyclic Carbene Catalyzed Oxidative Coupling of Alkenes/ α-Bromoacetophenones with Aldehydes: A Facile Entry to α,β-Epoxy Ketones

A novel, N-heterocyclic carbene (NHC) catalyzed direct oxidative coupling of styrenes with aldehydes has been described for the synthesis of α,β-epoxy ketones in good yields. This unprecedented regioselective oxidative coupling employs NBS/DBU/DMSO (DBU=1,8-diazabicyclo [5.4. 0] undec-7-ene, DMSO=dimethylsulfoxide, NBS=N-bromosuccinimide) as an oxidative system at ambient conditions. Additionally, first NHC-catalyzed Darzens reaction of α-bromoketones and aldehydes under mild reaction conditions has also been described. Interestingly, mechanistic studies have revealed the preferred reactivity of NHC with alkene/α-bromoketone rather than aldehydes, thus proceeding via the ketodeoxy Breslow intermediate.

Darzens reaction rate enhancement using aqueous media leading to a high level of kinetically controlled diastereoselective synthesis of steroidal epoxyketones

Darzens reactions between halocarbonyls and aldehydes have been carried out in water in the presence of a Li+-containing base, a phase-transfer catalyst, and granular polytetrafluoroethylene under mechanical stirring. Reactions using both aromatic and aliphatic aldehydes produced epoxides stereoselectively in good to excellent yields. This is the first time that aliphatic aldehydes with α-H have been used in aqueous Darzens reactions. The Darzens reactions were much faster in water than in organic solvents. This aqueous rate enhancement occurred for Darzens reactions between enantiopure steroidal haloketones and aldehydes, yielding enantiopure spiroepoxides with a high level of kinetically controlled diastereoselectivity. Chromatography was avoided in the purifications of the steroidal spiroepoxides. This is an example of preparing enantiopure epoxyketones via aqueous Darzens reaction using chiral α-haloketone substrates.