42393-40-8

Upstream product

• 26631-70-9 cis-2,3-dibromopropenoic acid methyl ester 
• 873-77-8 (4-chlorphenyl)magnesium bromide 
• 67-56-1 methanol 
• 104-88-1 4-chlorobenzaldehyde 
• 287481-44-1 methyl 2-(bis(2,2,2-trifluoroethoxy)phosphoryl)-2-bromoacetate 

Downstream Products

• 201413-18-5 (E)-5-butyl-3-[1-(4-chlorophenyl)methylidene]-3H-furan-2-one 
• 70041-47-3 (E)-3-(4-chlorobenzylidene)-5-phenylfuran-2(3H)-one 
• 42393-39-5 (Z)-2-bromo-3-(4-chlorophenyl)propenoic acid 

Relevant academic research and scientific papers

Versatile Transformations of α,β-Dibromoesters and Ketones in Basic Media under Microwave Irradiation

Depending on the reaction medium, α,β-dibromoesters under microwave irradiation may selectively lead to α-bromoalk-enes, to alkenes or to (E)-β-bromostyrenes. The corresponding ketones give selectively the α-bromoketones.

α-hypervalent iodine functionalized phosphonium and arsonium ylides and their tandem reaction as umpolung reagents

α-Hypervalent iodine functionalized phosphonium and arsonium ylides 2 can be used as umpolung ylides to react with nucleophiles to give α-heteroatom substituted ylides 4 in good yields. The nucleophilic substitution - Wittig tandem reaction of 2 can occur smoothly to provide an efficient method for the synthesis of (Z)-α-halo-α,β-unsaturated enoates or enones 6, stereoselectively.

A highly stereoselective synthesis of (E)-α-bromoacrylates

Novel reagent, methyl bis(2,2,2-trifluoroethoxy)bromophosphonoacetate (5a), was designed and prepared in order to efficiently synthesize (E)-α-bromoacrylates 7, from which widely useful precursors for various C-C bond formations were prepared. Horner-Wadsworth-Emmons (HWE) reaction of various aldehydes with 5a in the presence of t-BuOK and 18-C-6 gave corresponding (E)-α-bromoacrylate derivatives with high stereoselectivity and excellent yield. Using the product (E)-α-bromoacrylate 7s as a key intermediate, we succeeded in developing the most effective route of plaunotol synthesis via Suzuki cross-coupling. (C) 2000 Elsevier Science Ltd.

Isomerisation of methyl (E) 2-bromo-3-(4-XC6H 4)-propenoates

The geometric isomerisation of the title compound induced by bromine or chlorine appears to involve ionic pair species resulting from the nucleophilic attack of the halogen.

Studies on the transition metal-catalyzed synthesis of variously substituted (E)-3-[1-(aryl)methylidene]- and (E)-3-(1-alkylidene)-3H-furan-2-ones

5-Aryl and 5-alkyl substituted (E)-3-[1-(aryl)methylidene]- and (E)-3-(1-alkylidene)-3H-furan-2-ones, (E)-9, have been selectively synthesized by cyclization of the corresponding (E)-2-(1-alkynyl)-3-aryl/alkylpropenoic acids, (E)-11, in the presence of AgNO3 or Pd-catalysts such as trans-di(μ-acetato)bis[(di-o-tolylphosphino)benzyl]dipalla-dium(II) or that constituted of a mixture of Et3N and PdCl2(PhCN)2 or PdCl2(CH3CN)2. in a 3:1 molar ratio, respectively. A representative (E)-5-aryl-3-[1-(aryl)methylidene]-3H-furan-2-one, i.e. (E)-9i, has been also prepared by a tandem process involving a Pd(0)- and Cu(I)-catalyzed cross-coupling reaction between an 1-alkyne and a (Z)-3-aryl-2-bromopropenoic acid followed by a catalytic intramolecular oxypalladation of the resulting cross-coupled product. However, when this same approach was used to prepare an (E)-5-alkyl-3-[1-(aryl)methylidene]-3H-furan-2-one, i.e. (E)-9j, a mixture of (E)-9j and the corresponding (E)/(Z)-5-(1-alkylidene)-3-(aryl)methyl-5H-furan-2-one, i.e. (E)/(Z)-20, was obtained. Finally, in an attempt to prepare an (E)-4-alkyl-5-aryl-3-[1-(aryl)methylidene]-3H-furan-2-one, i.e. (E)-14a, by a tandem process involving the intramolecular oxypalladation of an (E)-enynoic acid, (E)-11, followed by a cross-coupling reaction of the resulting compound with aryl iodide, a (Z)-5-(1-alkynyl)-4-aryl-3-arylmethyl-5H-furan-2-one, i.e. (Z)-22, has been stereoselectively obtained.

Stereoselective synthesis of (2Z)-α-bromo-α,β-unsaturated esters via arsonium ylide

(2Z)-α-Bromo-α,β-unsaturated esters 6 can be synthesized stereo-selectively via arsonium ylides in good yields.