Ruthenium complexes are remarkable catalysts for the C–H activation approaches and organic transformations. Combining a Ru-catalyst with oxidants other additives in one-pot process is considered sustainable approach due to reduction reaction steps minimal usage of solvents during synthesis, work-up, isolation chemicals, purification products. This review highlights ruthenium-catalyzed transform...

In the title compound, C(32)H(37)NO(8), the central pyran ring adopts a twist-boat conformation and the 1,3-dioxoane rings adopt envelope conformations. The acenaphthyl-enone unit and two C atoms of a pyrrolidine ring are disordered over two sets of sites [occupancy ratio 0.669 (7):0.331 (7)]. The major fraction of the disordered pyrrolidine ring exhibits an envelope conformation while the mino...

In the mol-ecule of the title compound, C(20)H(11)ClN(2)O(3), the pyran ring adopts a flattened-boat conformation. In the crystal structure, inter-molecular N-H⋯N and N-H⋯O hydrogen bonds generate edge-fused R(2) (2)(12) and R(2) (2)(14) ring motifs; the hydrogen-bonded motifs are linked to each other, forming a three-dimensional network. A π-π contact [centroid-to-centroid distance = 3.879 (3)...

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, C25H27FO3, each of the cyclo-hexenone rings adopts a half-chair conformation, whereas the six-membered pyran ring adopts a flattened boat conformation, with the O and methine C atoms deviating by 0.0769 (15) and 0.196 (2) Å, respectively, from the plane of the other four atoms (r.m.s. deviation = 0.004 Å). The C=C double bond adopts an E conformation. The dihedral angle b...

An efficient diastereoselective approach for the synthesis of functionalized 3,4-dihydro-2H-pyran-4-carboxamides with variable frame was developed based on the reaction of available 4-oxoalkane-1,1,2,2-tetracarbonitriles (adducts of TCNE and ketones) with aldehydes in an acidic media. An unusual process of quasi hydrolysis of the cyano group was observed in the course of the described regio- an...

In the title compound, C24H15BrO3, the pyran-ochromenone ring is essentially planar, while the 2-bromo-phenyl group is almost perpendicular to it [85.58 (6)°]. In the crystal, inversion dimers linked by pairs of weak C-H⋯π bonds occur; there is also a short inter-atomic contact found between the Br and carbonyl O atoms [3.016 (1) Å].

In the title compound, C(14)H(19)N(3)O(4), the perhydro-pyran ring adopts a chair conformation. An intra-molecular C-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal packing, mol-ecules are linked by O-H⋯O hydrogen bonds, forming infinite chains along [100].

In the racemic title compound, C16H14O3, the ring of the 4-hy-droxy-benzyl substituent group forms a dihedral angle of 80.12 (12)° with the benzene ring of the chromanone system. Two C atoms of the pyran-one ring and the H atoms on the benzyl α-C atom are disordered over two sites, with site-occupation factors of 0.818 (8) and 0.182 (8). The crystal structure is stabilized by O-H⋯O hydrogen bon...

In the title compound, C(18)H(20)O(4),the pyran ring of the chromene unit adopts a half-chair conformation. An intra-molecular O-H⋯O hydrogen bond occurs. In the crystal, mol-ecules are linked along the b axis by C-H⋯O hydrogen bonds.