153864-76-7

Upstream product

• 145822-68-0 (E)-[2-ethoxy-3-(ethoxycarbonyl)-2-propenylidene]triphenylphosphorane 
• 536-38-9 4-chlorobenzoylmethyl bromide 
• 4998-15-6 4-chlorophenylglyoxal 
• 178754-83-1 (E)-3-Ethoxy-4-(triphenyl-λ⁵-arsanylidene)-but-2-enoic acid ethyl ester 
• 35471-23-9 ethyl (E)-4-bromo-3-ethoxy-2-butenoate 
• 172508-54-2 ethyl (2E,4E)-3-ethoxy-5-formyl-2,4-pentadienoate 
• 178899-78-0 ethyl (2E,4Z)-3-ethoxy-5-formyl-2,4-pentadienoate 
• 873-77-8 (4-chlorphenyl)magnesium bromide 
• 178754-88-6 (2E,4E)-6-(4-Chloro-phenyl)-3-ethoxy-6-hydroxy-hexa-2,4-dienoic acid ethyl ester 

Relevant academic research and scientific papers

Synthesis and reactions of ethyl 6-aryl-3-ethoxy-6-oxo-2,4-hexadienoates

Biologically interesting ethyl 6-aryl-3-ethoxy-6-oxo-2,4-hexadienoates (I) have been prepared by the Wittig reaction of [3-(ethoxycarbonyl)-2-ethoxy-2- propenylidene]triphenylphosphoranes (3a and 3b) and -arsorane (3c) with glyoxal monohydrates (5) and by oxidation of 6-aryl-3-ethoxy-6-hydroxy-2,4- hexadienoate (9) with activated manganese (IV) oxide supported by silica. Reaction of la with 3c gave 3-(4-chlorobenzoyl)-1,2-trans (and cis)-bis(1- ethoxy-2-ethoxycarbonylethenyl)cyclopropanes (6 and 7). When l a was treated with a 1: 5 mixture of concentrated HCI and tetrahydrofuran at room temperature, 3-hydroxy-6-oxo-2,4-hexadienoate (10a) was obtained in 46% yield. Treatment of 1b with trifluoroacetic acid Rave 5,6-dihydro-2H-pyran- 2-one (12) in 53% yield together with [0b in 28% yield. When la was treated with 1 N ethanolic potassium hydroxide, 12 and 2H-pyran derivative (13) were obtained in 33% and 28% yields, respectively. Reaction of la with ammonium hydroxide and primary amines in the presence of a proton acid gave 2-oxo- 1,2,5,6-tetrahydropyridines; (14) in good yields. The mechanism of the formation of 6, 12, 13, and 14 is discussed.

Allylidenetriphenylphosphorane as a Bifunctional Reagent: Synthesis of Cyclopentenones and α,β-Unsaturated Ketones with (3-(Alkoxycarbonyl)-2-ethoxy-2-propylidene)triphenylphosphorane

When (3-(ethoxycarbonyl)-2-ethoxy-2-propenylidene)triphenylphosphorane (6) was allowed to react with α-bromo ketones 8a-d in dichloromethane in the presence of Cs2CO3 at room temperature, a annulation occured and led to the formation of the corresponding 2-ethoxycyclopentadienes 9a-d in excellent yields.Similarly, bromo thioester 8g underwent the annulation to give 4-(ethylthio)cyclopentadiene 9g.Secondary bromides 2-bromo-3-pentanone and 2-bromocyclohexanone also afforded tetrasubstituted cyclopentadienes 9e and 9f in moderate yields when 2 equiv of 6 was used.The annulation is belived to proceed through a sequence involving a stepwise alkylation at the γ position of 6 and an intramolecular Wittig reaction because of the fact that intermediate 11 was isolated.The resulting 2-ethoxycyclopentadienes 9a-g were converted quantitatively into the corresponding cyclopentenones 10a-g upon mild acid treatment.Furthermore, allylidenetriphenylphosphorane underwent a carbon elongation at both ends of the three-carbon unit via an alkylation-Wittig reaction sequence. (3-(tert-Butoxycarbonyl)-2-ethoxy-2-propenylidene)triphenylphosphorane (7) reacted first with alkyl halides and then with aldehydes in the presence of Cs2CO3 to give enol ethers 23a-f, which were converted into α,β-unsaturated ketones 20, 21, and 25c-f by hydrolysis of the enol ether and then decarboxylation.In this way, shogaol (29), the pungent principle component of ginger, was conveniently synthesized starting from 2-methoxy-4-methylphenol.