Asymmetric allylic alkylation is a powerful reaction that allows the enantioselective formation of C-C bonds. Here we describe the asymmetric alkylation of alkylzirconium species to racemic 3,6-dihydro-2H-pyrans. Two systems were examined: 3-chloro-3,6-dihydro-2H-pyran using linear optimization (45-93% ee, up to 33% yield, 5 examples) and 3,6-dihydro-2H-pyran-3-yl diethyl phosphate with the ass...

The title compound, C17H11ClN2O2, which contains two stereogenic C atoms, crystallizes in a centrosymmetric space group as a racemate. The pyran ring and the isoxazole ring adopt sofa and twisted conformations, respectively. The dihedral angle between the benzene ring and the mean plane through the near coplanar atoms of the pyran ring is 4.17 (5)°. The mol-ecular conformation features a weak C...

The title compound, C(22)H(18)ClN(3)S, was synthesized by the reaction of 4-chloro-benzaldehyde, tetra-hydro-thio-pyran-4-one and 3-methyl-1-phenyl-1H-pyrazol-5-amine in acetic acid without a catalyst. The pyridine and pyrazole rings are almost coplanar, the dihedral angle between their mean planes being 2.50 (1)°. The thio-pyran ring exhibits an envelope conformation. The crystal packing is st...

In the title compound, C(11)H(9)Cl(2)N(3)O(5), the dihydro-pyran ring adopts a near-half-chair conformation. The benzene ring makes a torsion angle of 5.02 (5)° with the dihydro-pyran ring. Adjacent mol-ecules are inter-linked through inter-molecular C-H⋯O, N-H⋯O and C-Cl⋯π [3.4743 (9) Å] inter-actions. The inter-molecular N-H⋯O hydrogen bond generates an R(2) (2)(12) motif, which is observed t...

In the xanthenone system of the title compound, C23H20O4, the pyran ring has a maximum deviation of 0.111 (1) Å from planarity and the outer cyclo-hexene ring exhibits a puckered conformation. The three methyl-ene C atoms of the cyclo-hexene ring bonded to the pyran unit are disordered over two sets of sites [occupancies = 0.570 (3) and 0.430 (3)]. In the crystal, mol-ecules are linked by C-H⋯O...

In the title compound, C11H7ClO3, a chlorinated and methyl-ated 3-formyl-chromone derivative, the non-H atoms are essentially coplanar (r.m.s. deviation = 0.0670 Å), with the largest deviation from the least-squares plane [0.2349 (17) Å] being for the pyran carbonyl O atom. In the crystal, mol-ecules are linked through π-π stacking inter-actions along the a axis [centroid-centroid distance betw...

The title compound, C(20)H(21)NO(7), is asymmetric with a chiral centre located in the pyran ring and crystallizes as a racemate. The mol-ecular framework is somewhat bent; the coumarin moiety and the pyran ring are inclined by 7.85 (5)°. The mol-ecular structure is characterized by an intra-molecular N-H⋯O hydrogen bond, which generates an S(6) ring motif, and the crystal packing is stabilized...

In the cation of the title organic ion pair compound, C(23)H(20)ClN(2)O(3) (+)·CH(3)O(-), the cyclo-hexyl ring shows a half-boat conformation and the dihedral angles between two benzene rings and the pyran ring are 83.14 (7) and 73.18 (9)°. In the crystal, centrosymmetrically related cations are linked into a dimer by pairs of N-H⋯N hydrogen bonds, generating an R(2) (2)(12) ring motif. The ani...

The rearrangement under oxidative conditions of 3-(benzyloxy)-tetrahydro- 2,6,6-trimethyl-2H-pyran-2-carbaldehydes to afford a chiral protected tetrahydrofuran lactol is described.

Transition metal complexes containing bidentate O,O donor ligand, i.e. 3-[3-(4-chlorophenyl)4-hydroxy-6-methyl-pyran 2-one derived from 3-acetyl-6-methyl-pyran-2,4(3H)-dione (dehydroacetic acid) and p-chlorobenzaldehyde,have been synthesized and characterized by elemental analyses, conductometry, thermal analysis, magnetic,IR, UV-Vis and fungicidal study. From the analytical and thermal data, t...