By the use of an N-heterocyclic carbene copper(I) complex as a catalyst, the boracarboxylation of various alkynes (e.g., diaryl alkynes, aryl/alkyl alkynes, and phenylacetylene) with a diborane compound and carbon dioxide has been achieved for the first time, affording the α,β-unsaturated β-boralactone derivatives regio- and stereoselectively via a borylcupration/carboxylation cascade. Some imp...

The title compound, C(23)H(25)NSi, has an eight-membered silicon-containing heterocyclic ring with an intra-molecular N⋯Si close contact, the transannular distance of which is 2.6294 (18) Å. The resulting geometry about the Si atom is distorted trigonal-bypyramidal, with the N and H atoms occupying apical sites. The dihedral angle between the aromatic rings fused to the eight-membered ring is 6...

In the title compound, C(16)H(11)NO(2)S(2), the dihedral angles between the heterocyclic ring and the phenyl and anilinic benzene rings are 9.68 (13) and 79.26 (6)°, respectively, and an intra-molecular C-H⋯S inter-action occurs. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds occur, leading to R(2) (2)(10) loops, and C-H⋯O and weak C-H⋯π inter-actions further consolida...

In the crystal structure of the title compound, C(21)H(24)I(2)N(2)O(2), the two N atoms of the imidazolidine moiety are linked to the hy-droxy groups by intra-molecular O-H⋯N hydrogen-bonding inter-actions. The cyclo-hexane ring adopts a chair conformation and the heterocyclic ring to which it is fused has a twisted envelope conformation.

In the mol-ecule of the title compound, C(10)H(9)Br(2)NO(3)S, the S atom is four-coordinated in distorted tetra-hedral configuration. The heterocyclic thia-zine ring adopts a twist conformation. An intra-molecular C-H⋯O hydrogen bond results in the formation of a non-planar five-membered ring. In the crystal structure, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into infinite chain...

The pyrrolidine-2,5-dione ring in the title compound, C(15)H(15)NO(6), is in a twisted conformation with the acetyl C atoms projecting to opposite sides of the ring. The acetyl groups lie to opposite sides of the five-membered ring. The benzene ring is roughly perpendicular to the heterocyclic ring, forming a dihedral angle of 76.57 (14)° with it. In the crystal, mol-ecules are connected throug...

In the title compound, C(23)H(24)O(8)·H(2)O, the six-membered ring of the oxan-4-one (tetra-hydro-pyran-4-one) ring displays an envelope conformation with the heterocyclic O atom at the flap position. The dihedral angles between the terminal benzene rings is 37.23 (10)°. Classical intermolecular O-H⋯O and weak C-H⋯O hydrogen bonds are present in the crystal structure.

In the title compound, C(21)H(18)BrNO, both heterocyclic rings, viz. the hydro-pyridine ring and the adjacent hydro-furan ring, adopt envelope conformations. These two heterocycles make a dihedral angle of 37.3 (1)°. The dihedral angle between the hydro-pyridine and benzene rings is 69.6 (1)°. In the crystal, adjacent mol-ecules are linked by pairs of inter-molecular C-H⋯O hydrogen bonds, formi...

in the title compound, C(16)H(15)N(2) (+)·PF(6) (-), a precursor of N-heterocyclic carbene, the phenyl and benzyl rings are twisted away from the central imidazolium ring system, making dihedral angles of 70.30 (8) and 32.03 (10)°, respectively. The crystal structure is stabilized by C-H⋯F hydrogen bonds. Furthermore, P-F⋯π inter-actions involving imidazolium rings are observed [F⋯π = 2.9857 (1...

In the mol-ecule of the title compound, C(12)H(6)N(2)O(3)S, the central heterocyclic ring is oriented at dihedral angles of 3.25 (6) and 2.28 (7)° with respect to the benzene and pyridine rings, respectively. The dihedral angle between the benzene and pyridine rings is 5.53 (7)°. In the crystal structure, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into chains.