Anton V. Stepanov

Expedient Access to Functionalized Furan/3(2H)-furanone Ensembles via Microwave-Assisted Domino Reactions

Abstract A one-pot linkage between furan and 3(2H)-furanone rings has been effected via the microwave-assisted Et3N-catalyzed domino condensation of the furan and benzofuran carboxylic acids with available cyanopropargylic alcohols (MeCN, 100 °C, 1.2 atm, 2–17 h). Despite involving a number of C-H-forming/breaking steps, the assembly is chemoselective and the final products, 5-(2-furyl)-3(2H)-furanones, are formed in 59–96% yields. GRAPHICAL ABSTRACT

One-pot stereoselective tandem assembly of functionalized furan-3(2H)-one from γ-hydroxyalk-2-ynenitriles and 3-hydroxybenzoic acid

Abstractγ-Hydroxyalk-2-ynenitriles react chemo-, regio-, and stereoselectively with 3-hydroxybenzoic acid under mild conditions (Et3N, MeCN, 20–25°C, 48–144 h) giving 4-oxo-2-{3-[(1Z)-(1-cyanoalk-1-en-2-yl)oxy]-phenyl}-4,5-dihydrofuran-3-carbonitriles in 60–75% yields. The reaction opens a simple path to a new group of furan-3(2H)-one derivatives with pharmacophore functions.

Furfuryl vinyl ethers in [4+2]-cycloaddition reactions

For the first time [4+2]-cycloaddition reactions were carried out between furfuryl vinyl ethers and typical dienophiles and heterodienes proceeding in uncatalyzed conditions and resulting in previously unknown heterocyclic systems containing either free vinyloxy groups or furfuryl substituents. With maleic anhydride and maleimide furfuryl vinyl ethers afforded 1-(vinyloxyalkyl)tricyclodec-8-ene-3,5-diones in up to 72% yields, and with N-benzylideneaniline or acrolein the corresponding functionally substituted tetrahydroquinolines (yield up to 65%) or 3,4-dihydropyrans (yield 23–50%) were obtained.

Cycloadducts of methyl hydroxyalkynoates and DBU: Transformation into tethered furan-2(5 H )-one and caprolactam structures

Cycloadducts of 1,8-diazabicyclo[5.4.0]undec-7-ene and methyl 4-hydroxyalk-2-ynoates, octahydro-5H,9H-[1,3]oxazolo[2′,3′: 2,3]pyrimido[1,2-a]azepines, in the presence of potassium hydroxide in aqueous ethanol were converted to structures in which furan-2(5H)-one and caprolactam rings are linked to each other through an aminopropane tether.