76089-31-1

We report what to our knowledge is the smallest bis-calix[4]pyrrole (2). It proved capable of trapping fluoride anions exclusively relative to other anions (Cl-, Br-, SCN-, NO3-, H2PO4-, HSO4-, SO42-, and HP2O73- tetrabutylammonium salts), as confirmed by 1H NMR spectroscopy (CDCl3), X-ray diffraction analysis, DFT calculations, and molecular dynamics simulations. The F- selectivity is ascribed to the small size of the cavity in 2.

Diazoacetone reacts with methyl acrylate in the presence of anhydrous GaCl3 to give isomeric methyl 2-acetylcyclopropanecarboxylates rather than pyrazolines obtained from diazo esters or by noncatalytic reactions. In a similar reaction, diazoacetophenone yields methyl 2-benzoylcyclopropanecarboxylates, benzoylmethyl acrylate, and benzoylmethyl 2-benzoylcyclopropanecarboxylate via partial transesterification. Addition of an equimolar amount of GaCl3 to diazoacetone in the system CH2Cl2-HCl-H2O unexpectedly produces 4,5-dimethylfuran-3(2H)-one and 1,1'-oxybis(propan-2-one).

We report a new strategy for organocatalytic cascade reactions. Accordingly, enamine catalysis, iminium catalysis, and Bronsted acid catalysis can work in concert in a highly enantioselective organocatalytic cascade sequence toward chiral cis-3-substituted cyclohexylamines. We found that an achiral amine in combination with a catalytic amount of a chiral Bronsted acid can accomplish an aldol addition-dehydration-conjugate reduction-reductive amination to provide potential intermediates of pharmaceutically active compounds in good yields and excellent enantioselectivities. Copyright

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5-Substituted 2H-pyran-3(6H)-ones have been synthesised by intramolecular aldol condensation of diacetonyl and acetonyl phenacyl ethers which were accessible by hydration of corresponding 2-propynyl ethers.