85658-00-0Relevant academic research and scientific papers
β-Bromoenol phosphate as a new precursor for the modular regioselective synthesis of substituted furans
Fernandes, Rushil,Mhaske, Krishna,Narayan, Rishikesh
supporting information, (2021/11/24)
Owing to its importance in various realms of chemistry, furan occupies a position of eminence among heterocycles. Despite the availability of many methodologies for the synthesis of variably substituted furans, a modular convenient synthesis of 2,4-disubstituted furans remains challenging. The present work attempts to bridge that gap through a novel annulation-based approach using feedstock chemicals such as methyl ketones and their easily available derivatives, β-bromoenol phosphates. We have demonstrated a hitherto unknown reactivity of β-bromoenol phosphates which is responsible for the observed regioselectivity. The reaction requires only sodium hydride as the base under mild conditions. The scope of the reaction was found to be broad with the possibility of obtaining even tri-substituted furans besides a variety of 2,4-disubstituted furans. The methodology was applied to obtain synthetically challenging 3-acylfuran derivatives as well. The newly developed methodology is characterized by the modularity, regioselectivity as well as its practicality owing to easily available starting materials and fast reaction times.
Suzuki-Miyaura cross-coupling reaction of 1,2-oxaborol-2(5H)-ols with carboxylic anhydrides: A new method to furans
Yu, Tao,Wu, Xin-Yan,Yang, Jun
supporting information, p. 4071 - 4074 (2014/07/22)
An efficient one-step method has been developed to construct furans via a Suzuki-Miyaura cross-coupling reaction of 1,2-oxaborol-2(5H)-ols with carboxylic anhydrides. In the presence of Pd(OAc)2/PCy3, the multi-substituted alkenylboron compounds could couple with anhydrides to obtain furans in moderate-to-good yields. The addition of bases promoted the coupling reaction, and the plausible reaction mechanism was proposed.
Synthesis of 2,4-disubstituted furans and 4,6-diaryl-substituted 2,3-benzo-1,3a,6a-triazapentalenes
Katritzky, Alan R.,Hür, Deniz,Kirichenko, Kostyantyn,Ji, Yu,Steel, Peter J.
, p. 109 - 121 (2016/07/15)
Reactions of acylacetylenes 1a-h with benzotriazole 2 give intermediates 3a-h. The treatment of 3a-h with trimethylsulfonium iodide in the presence of base give intermediate oxiranes 4a-h and 2,3-benzo-1,3a,6a-triazapentalenes 7d-g depending on substituent. Acid-catalyzed rearrangement of crude 4a-h give 2,4-disubstituted furans 5a-h.
Silylation of γ-nitro ketones as a convenient approach to the synthesis of 2-[N,N-bis(silyloxy)amino]-2,3-dihydrofurans and conjugated enoximes
Birin,Tishkov,Ioffe,Strelenko,Tartakovsky
, p. 647 - 658 (2007/10/03)
Silylation of γ-nitro ketones of the general formula R 1COCH(R2)CH(R3)CH(R4)NO2 proceeded stereoselectively to give 2-[N,N-bis(trimethylsilyloxy)amino]-2,3- dihydrofurans, conjugated enoximes, silylation products of the carbonyl group or both functional groups, or N,N-bis(trimethylsilyloxy)enamine depending on the nature and positions of the substituents in the carbon skeleton. Dihydrofuran derivatives are formed for R1 = Ar or cyclo-C 3H5. Enoximes are generated as the silylation products of the starting ketones with enhanced β-proton mobility (R3 = CO2Me or 4-NO2C6H4). The presence of an alkyl group at the carbonyl function (R1 = Alk) is favorable for the formation of enoximes. Finally, the introduction of a substituent at the α position with respect to the nitro group (R4 = Me, CO2Me, or Ph) leads to the formation of silyl enolates. Under the action of NH4F in MeOH, dihydrofurans can be transformed into substituted furans in moderate yields.
