A novel gold(III) and TfOH‐cocatalyzed reaction of ortho‐alkynylbenzaldehydes with cyclopropenes was described for the synthesis of a variety of functionalized benzo[7]annulene derivatives in a highly stereoselective manner. This reaction could undergo tandem [4+2] cycloaddition/ring expansion to achieve the construction of seven‐membered‐carbocycles, along with the cleavage of double bond of cyclopropenes. The reaction features simple operations, commercially available catalysts and broad substrate scope with good efficiencies.
We demonstrate a strategy that can provide isochromenes with an electron-deficient isoquinoline unit. The reactions feature simple operations, mild conditions and high yields.
The crystal structures of two adducts of 2-methoxycarbonylethyltin trichloride with hexamethylphosphoryltriamide (HMPA) and 1,10-phenanthroline (phen), CH
The complexes of 2-(menthoxycarbonyl)ethyltin chloride, MenOCOCH2CH2SnCl3⋅L (Men = Menthyl, L = benzyl phenyl sulfoxide (bpSO), 1; 2,2’-bipyridine (bpy), 2; 1,10-phenanthroline (phen), 3) and [MenOCOCH2CH2SnCl2(OCH3)]2 (4), have been synthesized and characterized by means of elemental analysis, FT-IR, NMR (1H, 13C and 119Sn) spectra. The crystal structures of 1, 3 and 4 have been determined by single crystal X-ray diffraction. The tin atoms in 1-4 are all hexa-coordinated. The tin atom in 1 adopts a distorted [CSnCl3O2] octahedral geometry with an oxygen atom of the ligand and an intramolecular coordination of the oxygen atom from the carbonyl group to the tin atom. Complex 3 possesses a distorted [CSnCl3N2] octahedral geometry with two nitrogen atoms of a chelating phen ligand. The carbonyl oxygen atom of the ester moiety is not coordinating. Compound 4 is a centrosymmetric dimer with a four-membered Sn2O2 ring, and the tin atom has a distorted [CSnCl2O3] octahedral geometry with an intramolecular C=O→Sn coordination and intermolecular methoxy bridging.
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