2892-42-4

Upstream product

• 13665-04-8 2,2-dibromoacetophenone 
• 98-86-2 acetophenone 
• 70-11-1 α-bromoacetophenone 
• 102921-26-6 (1,2-dibromoethyl)benzene 
• 100-42-5 styrene 
• 91523-92-1 2-((1-phenylvinyl)oxy)isoindoline-1,3-dione 
• 959-28-4 1,4-diphenylbut-2-ene-1,4-dione 
• 98-81-7 1-bromovinylbenzene 
• 14900-39-1 phenylvinylboronic acid 
• 1074-12-0 phenylglyoxal hydrate 
• 6048-29-9 triphenylphenacylphosphonium bromide 
• 19158-66-8 1-(2-oxo-2-phenylethyl)tetrahydrothiophenium bromide 
• 81477-94-3 N-(diphenylmethylene)glycine tert-butyl ester 

Relevant academic research and scientific papers

Cyclotrimerization for the Synthesis of Cyclopropanes

The synthesis of small rings by functionalization of C(sp3)-H bonds remains a great challenge. We report for the first time a copper-catalyzed [1+1+1] cyclotrimerization of acetophenone derivatives under mild reaction conditions. The reaction has a broad scope for the stereoselective synthesis of cyclopropanes by trimerization of acetophenone. The developed transformation is based on an extraordinary copper-catalyzed cascade process that allows saturated carbocycles to be obtained for the first time by cyclotrimerization through functionalization of C(sp3)-H bonds. The cascade of sixfold C(sp3)-H bond functionalization allows the synthesis of cyclopropanes in a highly stereoselective approach. Give it a tri: Copper-catalyzed oxidative [1+1+1] cyclotrimerization of acetophenone derivatives under mild reaction conditions and with a broad reaction scope has been developed. This transformation is a radical cascade process that allows saturated carbocycles to be obtained by cyclotrimerization through functionalization of C(sp3)-H bonds.

Rh(III)-catalyzed cyclopropanation initiated by C-H activation: Ligand development enables a diastereoselective [2 + 1] annulation of N-enoxyphthalimides and alkenes

N-Enoxyphthalimides undergo a Rh(III)-catalyzed C-H activation initiated cyclopropanation of electron deficient alkenes. The reaction is proposed to proceed via a directed activation of the olefinic C-H bond followed by two migratory insertions, first across the electron-deficient alkene and then by cyclization back onto the enol moiety. A newly designed isopropylcyclopentadienyl ligand drastically improves yield and diastereoselectivity.

One-pot synthesis of cyclopropane derivatives with a cis : Trans stereoselectivity by Wittig olefination-sulfur ylide cyclopropanation sequence

Cyclopropane derivatives were synthesised in one pot from aromatic aldehydes, phenacyltriphenylphosphonium bromide, and S-phenacylthiolanium bromide by a Wittig olefination-sulfur ylide cyclopropanation sequence. When Cs2CO3 was used as the base and CH3CN/water (8:2, v/v) as the solvent, the major product was the cis-1,2-dibenzoyl cyclopropane. In contrast, when using DBU as the base and MeOH as the solvent, the major product was transdibenzoyl cyclopropane. In some cases, the major isomer was obtained in high purity and good yield by simple filtration.

Electrophilic and nucleophilic side chain fluorination of para-substituted acetophenones

para-Substituted α-fluoroacetophenones have been synthesised by three different routes. Electrophilic fluorination of trimethylsilyl enol ethers of acetophenones using Selectfluor (F-TEDA-BF4, 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis-(tetrafluoroborate)) gave high to moderate yield depending on the electronic properties of the substituents. F-TEDA-BF4 mediated fluorination of acetophenones in methanol resulted in a mixture of α-fluoroacetophenones and the corresponding 2-fluoro-1,1-dimethyl acetals. The dimethyl acetals were hydrolysed using trifluoroacetic acid in water to maximise the yield of the product. Nucleophilic fluorination of α-bromoacetophenones using tetrabutylammonium hydrogen bifluoride (TBABF) led to moderate yield when having electron-donating substituents, whereas low yields were experienced when more electron-withdrawing substituents were introduced.

Enantioselective synthesis of aroylalanine derivatives

In this paper we report the development of a highly enantioselective method for the synthesis of aroylalanines. The approach described employs a protected 2-amino-4-bromopent-4-enoic acid, generated via the asymmetric phase-transfer catalyzed alkylation of a glycine imine, as a key intermediate. Suzuki coupling with an aryl boronic acid followed by ozonolysis of the resulting styrene provides efficient access to the aroylalanine derivatives. The utility of this methodology is illustrated by the synthesis of L-kynurenine along with several aroylalanine inhibitors of the kynurenine pathway.

Electrochemical reduction of 2,2-dibromoacetophenone

The cathodic reduction of 2,2-dibromoacetophenone in aprotic medium DMF-LiClO4 yields (E)-4,4-dibromo-1,3-diphenyl-2,3-epoxybutan-1-one as the major product and trans-1,2,3-tribenzoylcyclopropane through an ionic or carbene route, respectively.