94997-16-7

Upstream product

• 110055-24-8 1-(3,4-dimethoxy-phenethyl)-1,3,3a,4,5,6-hexahydro-indol-2-one 
• 932-03-6 1-Ethynyl-7-oxa-bicyclo[4.1.0]heptane 
• 120-20-7 2-(3,4-dimethoxyphenyl)-ethylamine 
• 108-94-1 cyclohexanone 
• 110452-14-7 2-phenylthiocyclohexanone 
• 651315-16-1 (2-oxo-1-phenylsulfanylcyclohexyl)-acetic acid ethyl ester 
• 219740-93-9 2,2,2-trichloro-N-cyclohex-1-enyl-N-[2-(3,4-dimethoxy-phenyl)-ethyl]-acetamide 
• 7446-08-4 selenium(IV) oxide 
• 64-17-5 ethanol 

Downstream Products

• 52358-58-4 (+/-)-3α,15,16-trimethoxy-8-oxo-Δ^1,6-erythrinan 
• 93946-59-9 7-bromo-1-[2-(3,4-dimethoxyphenyl)ethyl]-1,4,5,6-tetrahydro-2H-indol-2-one 

Relevant academic research and scientific papers

Oxidative Dearomatization of 4,5,6,7-Tetrahydro-1H-indoles Obtained by Metal- and Solvent-Free Thermal 5-endo-dig Cyclization: The Route to Erythrina and Lycorine Alkaloids

A facile one-pot approach based on a thermally induced metal- and solvent-free 5-endo-dig cyclization reaction of the amino propargylic alcohols in combination with Dess-Martin periodinane-promoted oxidative dearomatization of 4,5,6,7-tetrahydroindole intermediates provides an efficient and robust access to 5,6-dihydro-1H-indol-2(4H)ones. Green, relatively mild and operationally simple characteristics of the synthetic sequence are the major advantages, which greatly amplify the developed methodology. The utility of obtained indolones as unified key precursors is demonstrated by the application of these products to the formal total syntheses of a whole pleiad of Erythrina- and Lycorine-type alkaloids, namely (±)-erysotramidine, (±)-erysotrine, (±)-erythravine, (±)-γ-lycorane, and abnormal erythrinanes (±)-coccoline and (±)-coccuvinine.

Electrophilic-induced cyclization reaction of hexahydroindolinone derivatives and its application toward the synthesis of (±)- erysotramidine

A convenient synthesis of variously substituted octahydroindolo[7a,1a]- isoquinolinones has been achieved by an acid-induced cyclization of hexahydroindolinones bearing tethered phenethyl groups. The formation of a single lactam diastereomer is the result

Efficient synthesis of (+/-)-erysotramidine using an NBS-promoted cyclization reaction of a hexahydroindolinone derivative.

An NBS-promoted intramolecular electrophilic aromatic substitution reaction of a hexahydroindolinone derivative was used to assemble the tetracyclic core of the erythrinane skeleton. The resulting cyclized product was transformed into (+/-)-erysotramidine

Mn(III)/Cu(II)-mediated oxidative radical cyclization of α-(methylthio)acetamides leading to erythrinanes

Treatment of N-[2-(3,4-dimethoxyphenyl)ethyl]-α-(methylthio)acetamide 3 with Mn(OAc)3 in the presence of Cu(Oac)2 gave tetrahydroindol-2-one 4, which then cyclized with Mn(Oac)3 to give 4-acetoxyerythrinane 5. A similar reaction of the 3,4-methylenedioxyphenyl congener 8 also gave tetrahydroindol-2-one 9, which, however, gave only a trace amount of the Mn(OAc)3-mediated cyclization product 11 and afforded the oxidation product 10. On the basis of these results, formation of 5 from 4 was thought to proceed via nucleophilic attack of the pyrrole ring on the cation-radical IX, generated by a single electron-transfer reaction of the acetoxy-substituted intermediate V. Treatment of compound 16 with Mn(OAc)3/Cu(OAc)2 gave no erythrinane derivative with recovery of the starting material, indicating that the presence of a methylthio group of 4 is essential for effecting the formation of erythrinane 5. On the other hand, treatment of 3 with Mn(OAc)3 using Cu(OTf)2 as an additive in place of Cu(OAc)2 gave another erythrinane 17. This method was applied to a formal synthesis of 3-demethoxyerythratidinone (20), a naturally occurring Erythrina alkaloid.

Nickel powder promoted 5-endo radical cyclisations. A concise approach to erythrina alkaloids

N-Alkenyl trichloroacetamides 3 undergo, upon refluxing with nickel powder and acetic acid in 2-propanol, exclusive 5-endo-trig cyclisation to afford functionalised lactams 4; these are attractive precursors of erythrina alkaloids, as demonstrated by the expedient synthesis of 3- demethoxyerythratidinone 5.