Laura Torre-Fernández

Enantioselective Multicomponent Synthesis of Fused 6–5 Bicyclic 2‐Butenolides by a Cascade Heterobicyclisation Process

The successive coupling of an alkoxy(aryl/heteroaryl)carbene complex of chromium with either a ketone or an imide lithium enolate and then a 3-substituted (H, TMS, PhCH(2), PhCH(2)CH(2), Me) propargylic organomagnesium reagent has afforded novel hydroxy-substituted bicyclic [4.3.0]-γ-alkylidene-2-butenolides with three modular points that has allowed the efficient introduction of molecular complexity, including a homopropargylic alcohol core. The selective formation of these five- or six-component heterobicyclisation products is the result of the regioselective integration of the Grignard reagent as a propargyl fragment followed by a cascade CO/alkyne/CO insertion, ketene trapping and elimination sequence. By using lithium enolates of chiral N-acetyl-2-oxazolidinones and the corresponding propargylic organocerium reagents, both enantiomers of these bicyclic heterocycles were efficiently prepared with very high enantiomeric purity. Architecturally, these fused bicyclic butenolides are characterised by a highly unsaturated and oxygenated core and they exhibit strong blue fluorescence in solution.

An efficient green synthesis of dispirohydroquinolines via a diastereoselective one-pot eight-component reaction

Abstract The one-pot eight-component reaction between Meldrums acid, an aromatic aldehyde, and an aryl amine was achieved in the presence of citric acid catalyst. The corresponding dispirohydroquinolines were obtained in good yields with excellent diastereoselectivity. This method is a combination of the Knoevenagel and Michael reactions.

Stereoselective synthesis of 1′,5′,7′,8′-tetrahydro-2′ H ,4′ H -dispiro[[1,3] dioxane-5,3′-quinoline-6′,5′′-[1′′,3′′]dioxane]-4,4′′,6,6′′-tetrone derivatives in the presence of benzoic acid as an efficient catalyst via one-pot multicomponent reaction

A simple and efficient pseudo eight-component synthesis of 1′,5′,7′,8′-tetrahydro-2′H,4′H-dispiro[[1,3]dioxane-5,3′-quinoline-6′,5″-[1″,3″]dioxane]-4,4″,6,6″-tetrone derivatives is described. This reaction between, aromatic aldehydes, aromatic amines and Meldrums acid in the presence of benzoic acid as an efficient catalyst at ambient temperature affords the product in good yields.

N,N'-Dibenzyl-N''-(2,4-difluoro-benzo-yl)-N,N'-dimethyl-phospho-ric triamide.

The phosphoryl and carbonyl groups in the title compound, C23H24F2N3O2P, are anti to each other. The P atom is in a tetrahedral coordination environment and the environment of each N atom is essentially planar, the average bond angles at the two N atoms being 119.9 and 119.1°. The H atom of the C(=O)NHP(=O) group is involved in an intermolecular –P=O⋯H–N– hydrogen bond, forming centrosymmetric dimers.

N,N′-Dibenzyl-N,N′-dimethyl-N′′-(2-phenyl­acet­yl)phospho­ric triamide

The P atom in the title molecule, C24H28N3O2P, is in a distorted tetrahedral P(=O)(N)(N)2 environment. The phosphoryl group and the NH unit adopt a syn orientation with respect to each other and the N atoms have sp 2 character. The P—N bonds in the P(O)[N(CH3)(CH2C6H5)]2 unit are shorter than the P—N bond in the C(=O)NHP(=O) fragment. An intramolecular C—H⋯O hydrogen bond occurs. In the crystal, pairs of P=O⋯H—N hydrogen bonds form centrosymmetric dimers. C—H⋯O contacts are also observed. Four C atoms of two benzene rings are disordered over two alternative sites with an occupancy ratio of 0.523 (12):0.427 (12).

N,N'-Dibenzyl-N,N'-dimethyl-N''-(4-nitro-benzo-yl)phospho-ric triamide.

The P atom in the title compound, C23H25N4O4P, is in a slightly distorted tetrahedral coordination environment and the N atoms show sp 2 character. The phosphoryl group and the NH unit are syn with respect to each other. In the crystal, pairs of intermolecular N—H⋯O(P) hydrogen bonds form centrosymmetric dimers.

N-Benzoyl-N',N''-dicyclo-hexyl-phospho-ric triamide.

In the title compound, C19H30N3O2P, the central P atom has a distorted tetrahedral configuration. The N atoms in both cyclohexylamide moieties exhibit a slight deviation [0.32 (7) and 0.44 (6) Å] from planarity, while the benzoylamide N atom is planar [0.11 (3) Å]. In the crystal, molecules are linked via N—H⋯O(P) and N—H⋯O(C) hydrogen bonds, forming R 2 2(10) rings within linear arrangements parallel to the b axis.

5-Hy-droxy-7-phenyl-5-(prop-2-yn-1-yl)-5,6-dihydro-1-benzofuran-2(4H)-one monohydrate.

In the title compound, C17H14O3·H2O, the six-membered ring, which adopts a half-chair conformation, makes a dihedral angle of 24.3 (2)° with the phenyl ring. In the crystal, the components are linked by O—H⋯O hydrogen bonds involving the water molecule, and the hydroxy and carbonyl groups of the organic compound. These interactions form a square-like supramolecular synthon unit which propagates as chains parallel to the crystallographic b axis. A C—H⋯O interaction also occurs.

1,4-Bis(methyl­sulfan­yl)naphthalene

The molecule of the title compound, C12H12S2, is close to planar, with the methyl C atoms deviating by 0.019 (1) and 0.221 (2) Å from the naphthalene mean plane. In the crystal structure, the shortest S⋯S contact of 3.6864 (9) Å is longer than the van der Waals contact distance.

Naphthyridines as building blocks: the helix structure of 2-N-acetylamino-7-methyl-1,8-naphthyridine

24 European Crystallographic Meeting, ECM24, Marrakech, 2007 Page s154 Acta Cryst. (2007). A63, s154 systems are tris(diketonate) coordination compounds of trivalent metals. This was noticed as early as 1926 when has been noted that the crystal structures of trivalent metal pentane-2,4-dionato complexes of various metals appear to be grouped in several isomorphous series [2]. If the metal atom is coordinated by asymmetrical diketonate, two different isomers (facial and meridial) are possible. Our work concentrated on compounds where trivalent metals are coordinated by 1-phenylbutane-1,3-dionato ligands which were studied by single crystal X-ray diffraction and thermal analysis. The meridial complexes of iron(III), manganese(III), chromium(III) were already reported to be isomorphous based on their powder diffraction patterns [3]. We have shown that thay crystallize in the monoclinic system, space group P21/c. The only facial isomers which could be isolated where those of chromium(III) and cobalt(III) complexes. They were both found to crystallize in two pseudopolymorphic modifications. Pure compounds crystallize in the space group P–1 with two molecules in the asymmetric unit. The crystal structures of the chromium and cobalt compounds are almost identical. Under same crystallization conditions, both compounds can also crystallize as hydrates. The hydrates crystallize in the space group R–3 with 12 molecules per unit cell. The two symmetrically independent molecules in the structure differ in the mode of hydratation. As is the case with the triclinic modifications, the trigonal modifications of both chromium and cobalt compounds are almost perfectly isostructural