184151-87-9

Upstream product

• 20052-66-8 2,6-diphenyl-4H-pyran 
• 3238-03-7 (2-benzoylcyclopropyl)(phenyl)methanone 
• 1096497-16-3 (Z)-1,5-Diphenyl-pent-2-en-4-yn-1-ol 
• 1096497-78-7 (Z)-1,5-diphenyl-pent-2-en-4-yn-1-one 
• 17113-33-6 2-phenylfuran 
• 65-85-0 benzoic acid 

Relevant academic research and scientific papers

Highly efficient synthesis of multisubstituted 2-acyl furans via PIFA/I2-mediated oxidative cycloisomerization of cis -2-En-4-yn-1-ols

A novel oxidative cycloisomerization of cis-enynols has been developed using a combination of hypervalent iodine(III) reagent, molecular iodine, and a base. This method offers an efficient synthesis of 2-acyl furans with diverse substitution patterns in a -regioselective manner under mild reaction conditions. A mechanistic proposal for these transformations involving alkyne activation by trifluoroacetylhypoiodite generated in situ is presented. Georg Thieme Verlag Stuttgart · New York.

New synthetic approach for the construction of multisubstituted 2-acyl furans by the IBX-mediated cascade oxidation/cyclization of cis-2-En-4-yn-1-ols (IBX = 2-iodoxybenzoic acid)

A new approach for the construction of multisubstituted 2-acyl furans through cis-2-En-4-yn-1-ols (IBX=2-iodoxybenzoic acid)-mediated oxidation/cyclization in dimethyl sulfoxidse (DMSO) was developed. The results show that the introduction of an alkyl group at Cl provided a satisfactory yield of furan of 60% at 90°C. It is seen that IBX act as an electrophile to promote the cycloaddition of carbonyl group to the alkyne moiety. The furan derivatives are found to be useful synthetic intermediates for access to the compounds bearing biological activity. The studies also elucidate this reaction mechanism and extend the scope of synthetic utility of multisubstituted 2-acyl furans.

Cyclopropyl conjugation and ketyl anions: When do things begin to fall apart?

Results pertaining to the electrochemical reduction of 1,2- diacetylcyclopropane (5), 1-acetyl-2-phenylcyclopropane (6), 1-acetyl-2-benzoylcyclopropane (7), and 1,2-dibenzoylcyclopropane (8) are reported. While 6?- exists as a discrete species, the barrier to ring opening is very small (107 s-1. For 7 and 8, the additional resonance stabilization afforded by the benzoyl moieties results in significantly lower rate constants for ring opening, on the order of 10 5-106 s-1. Electron transfer to 8 serves to initiate an unexpected vinylcyclopropane → cyclopentene type rearrangement, which occurs via a radical ion chain mechanism. The results for reduction of 5 are less clear-cut: The experimental results suggest that the reduction is unexceptional, with a symmetry coefficient α ≤ 0.5, and reorganization energy consistent with a simple electron-transfer process (one electron reduction, followed by ring opening). In contrast, molecular orbital calculations suggest that 5?- has no apparent lifetime and that reduction of 5 may occur by a concerted dissociative electron transfer (DET) mechanism (i.e., electron transfer and ring opening occur simultaneously). These seemingly contradictory results can be reconciled if the increase in the internal reorganization energy associated with the onset of concerted DET is offset by a lowering of the solvent reorganization energy associated with electron transfer to a more highly delocalized LUMO.

One-step synthesis of 5-acylisothiazoles from furans

Premixed ethyl carbamate, thionyl chloride and pyridine (which generate thiazyl chloride, N≡SCl) in boiling benzene or toluene convert 2,5- and 2,3,5-substituted furans into 5-acylisothiazoles regiospecifically. The reactions are much faster and generally higher yielding in boiling chlorobenzene with more thionyl chloride and with pyridine or isoquinoline as base. Under the more vigorous conditions, even fully substituted 3-bromofurans give isothiazoles, with the displacement of bromine. Deactivated furans, with electron-withdrawing groups such as ester, cyano, benzoyl and phenylsulfonyl in the α-position, react under the more vigorous conditions to give 5-acylisothiazoles with the electronegative group in the 3-position. The 'activated' 2-methyl-5-phenyl- and 5-phenyl-2-phenylthio-furans react analogously, with the more electron-releasing group becoming part of the 5-acyl substituent, exclusively or predominantly. These results are explained by initial electrophilic attack of the furan ring to give a β-thiazyl derivative which spontaneously ring-opens and closes to the isothiazole. The X-ray structures of five of the differently substituted isothiazole compounds are reported. All have very similar patterns of bonding within their isothiazole rings that appear to be independent of the electron-withdrawing or -donating nature of the substituents. Three of the compounds (8a, 8g and 13) have loosely linked chain structures in the solid state, adjacent molecules being connected by combinations of hydrogen bonding and π-π stacking interactions.

Oxidation reactions of 4H-chalcogenopyrans

We have studied the oxidation of 4H-chalcogenopyrans and chalcogenopyrylium salts by lead tetraacetate. We have established that the major reaction products on oxidation of 2,6-diphenyl-4H-thiopyran and selenopyran are 2,6-diphenyl-4H-thio(seleno)pyran-4-