17235-14-2

Upstream product

• 939-18-4 3-bromo-2H-chromen-2-one 
• 917-54-4 methyllithium 
• 254-04-6 2H-chromene 
• 6093-67-0 5-hydroxycoumarin 
• 917-64-6 methyl magnesium iodide 
• 91-64-5 coumarin 
• 271-89-6 1-benzofurane 
• 67-64-1 acetone 

Downstream Products

• 398454-32-5 3-(2-hydroxyphenyl)-5,5-dimethyltetrahydrofuran-2-ol 
• 2513-25-9 2,2-dimethyl-2H-chromene 
• 36852-15-0 4-(2-Hydroxyphenyl)-3-methyl-1,3-butadien 

Relevant academic research and scientific papers

2H-chromenes generated by an iron(III) complex-catalyzed allylic cyclization

A straightforward method based on an iron(III) complex-catalyzed cyclization of 2-(1-hydroxyallyl)phenols is reported to access a large variety of 2H-chromenes. This method was applied to the total synthesis of a natural product, tephrowatsin B.

Stereoselective reductive opening of 2,3-benzofuran - A two-step synthesis of 2H-chromenes including deoxycordiachromene

The reaction of 2,3-benzofuran (1) with lithium and a catalytic amount of 4,4′-di-tert-butylbiphenyl (TDBB, 5 mol %) in THF at 0 °C leads to the stereoselective ring opening of the heterocycle, yielding the (Z)-organolithium derivatives (2) which, by reaction with different electrophiles [H2O, D2O, tBuCHO, PhCHO, Ph(CH2)2CHO, Me2CO, nPrCOMe, PhCOMe, (CH2)4CO] at -78 °C and final hydrolysis with water, give the expected (Z)-products 3. Cyclisation of the products obtained by reaction with carbonyl compounds under acidic conditions affords the expected substituted 2H-chromenes 4, including deoxycordiachromene 4j.

Photochemical Reactions of o-Alkenylphenols and 1-Alkenyl-2-naphthol with Alkylamines: Amination via Photoinduced Proton Transfer

Irradiation of o-alkenylphenols 1a-c and 2a-e in the presence of alkylamines gave o-(1-alkylaminoalkyl)phenols 4a-n and 5a-e in relatively good yields.Deprotonation of these o-alkenylphenols by the amines occurs in the excited singlet state to give the excited singlet state of the phenolate anion 7 and the ammonium ion.The proton transfer from the ammonium ion to the alkenyl group of 7 generates the zwitterion 8 that allows the nucleophilic addition of the amine at the benzylic cation centre.Similar photoamination of 1-(2-methylpropenyl)-2-naphthol 3 with alkylamines occured to give 1-(1-alkylamino-2-methylpropyl)-2-naphthols 6a-b.

Reaction of 3-Halogeno-2H-1-benzopyran-2-ones with Organometallic Compounds. Synthesis of 4-Alkyl-2H-1-benzopyran-2-ones. X-Ray Molecular Structure of 3-Bromo-3,4-dihydro-4-isopropylcoumarin

3-Halogeno-2H-1-benzopyran-2-ones react with magnesium, lithium, aluminium and copper derivatives to give 3,4-dihydrocuomarins and 3-(o-hydroxyphenyl)propenols as major products.The nature and the ratio of the products in the final mixture depend on the solvent and on the organometallic reagent.Grignard derivatives yield 1,4-monoalkylation compounds in tetrahydrofuran (THF) or 1,2-dialkylation derivatives in toluene.In some cases the dehalogenation competes with the 1,2-alkylation process in the reactions with alkyllithiums.The presence of the halogen at C-3 increases the reductive ability of organoaluminiums.In general, the reaction with lithium dialkylcuprates leads to complex mixtures of products.The 4-alkyl-3-halogeno-3,4-dihydrocuomarins obtained undergo dehydrohalogenation easily, and lead to 4-alkylcuomarins in good yields.The tandem alkylation-dehydrohalogenation of 3-halogeno-2H-1-benzopyran-2-ones constitutes a versatile synthesis of 4-alkylcuomarins.