Sc(OTf)3-catalyzed [3 + 2]-cycloaddition of nitrones with ynones.

An efficient approach to access functionalized (2,3-dihydroisoxazol-4-yl) ketones has been developed by reacting nitrones 4 with ynones 7 or terminal ynones 10 in a one-pot fashion. The reaction went through a formal Sc(OTf)3-catalyzed [3 + 2]-cycloaddition process to generate a number of functionalized (2,3-dihydroisoxazol-4-yl) ketones 11aa-11aw, 11ba-11la and 12aa-12ae in moderate to good yields.

Synthesis of the Sex Pheromone of the Tea Tussock Moth Based on a Resource Chemistry Strategy.

Synthesis of the sex pheromone of the tea tussock moth in 33% overall yield over 10 steps was achieved. Moreover, the chiral pool concept was applied in the asymmetric synthesis. The synthesis used a chemical available on a large-scale from recycling of wastewater from the steroid industry. The carbon skeleton was constructed using the C4+C5+C8 strategy. Based on this strategy, the original chiral center was totally retained.

Asymmetric Total Synthesis of Four Stereoisomers of the Sex Pheromone of the Western Corn Rootworm.

A convergent synthesis of four stereoisomers of the sex pheromone of the western corn rootworm (8-methyldecan-2-yl propionate, 1) from commercially available chiral starting materials is reported. The key step was Julia-Kocienski olefination between chiral BT-sulfone and chiral aldehyde. This synthetic route provided the four stereoisomers of 1 in 24-29% total yield via a six-step sequence. The simple scale-up strategy provides a new way to achieve the asymmetric synthesis of the sex pheromone.

Syntheses of Benzo[c]Chromen-6-ones by Palladium Catalyzed C-H Bond Activation using Diazonium Salts.

An efficient palladium catalyzed C-H bond activation for the synthesis of benzo[c]chromen-6-ones using diazonium salts is described. In the presence of Pd(OAc)2, dppp, PivOH and K2CO3, the diazonium salt can be transformed into the product through a denitrogenation/C-H bond activation/cyclization sequence in acetonitrile. Altogether, nine structurally diverse substituted benzoLc]chromen-6-ones were prepared in excellent yields through two different methods.

Divergent Method to trans-5-Hydroxy-6-alkynyl/alkenyl-2-piperidinones: Syntheses of (-)-Epiquinamide and (+)-Swainsonine.

An efficient diastereoselective approach to access trans-5-hydroxy-6-alkynyl/alkenyl-2-piperidinones has been developed through nucleophilic addition of α-chiral aldimines using alkynyl/alkenyl Grignard reagents. The diastereoselectivity of alkenyl in C-6 position of 2-piperidinone was controlled by α-alkoxy substitution, while the alkynyl was controlled by the coordination of the α-alkoxy substitution and stereochemistry of sulfinamide. The utility of this straightforward cascade process is demonstrated by the asymmetric synthesis of the (-)-epiquinamide and (+)-swainsonine.

Diastereoconvergent synthesis of trans-5-hydroxy-6-substituted-2-piperidinones by addition-cyclization-deprotection process.

A diastereoselective one-pot approach to access trans-5-hydroxy-6-substituted-2-piperidinones by an addition-cyclization-deprotection process has been developed, in which the stereogenic center at the C-6 position was solely controlled by α-OTBS group. The utility of this transformation is demonstrated by the asymmetric synthesis of the enantiomer of (-)-CP-99,994.

A facile synthesis of (+/-)-heliannuol-D.

A facile synthesis of (+/-)-heliannuol-D 1, which serves as an allelopathic chemical in nature and a potential lead compound in the search for new herbicides, has been achieved in a linear 11 steps, together with its epimer. The synthesis commenced with 4-methoxy-3-methyl-acetophenone, through the Baeyer-Villiger reaction, lithiation and addition, epoxidation and intramolecular cyclization to give (+/-)-heliannuol-D (1) and its epimer (la) in 32.6% overall yield. Our synthetic approach is cost-effective; this will be helpful in applying this kind of compound for the development of a new generation of agrochemicals.

A facile and efficient synthesis of diaryl amines or ethers under microwave irradiation at presence of KF/Al2O3 without solvent and their anti-fungal biological activities against six phytopathogens.

A series of diaryl amines, ethers and thioethers were synthesized under microwave irradiation efficiently at presence of KF/Al2O3 in 83%-96% yields without any solvent. The salient characters of this method lie in short reaction time, high yields, general applicability to substrates and simple workup procedure. At the same time, their antifungal biological activities against six phytopathogen were evaluated. Most of the compounds (3b, 3c, 3g-o) are more potent than thiophannate-methyl against to Magnaporthe oryzae. This implies that diaryl amine or ether moiety may be helpful in finding a fungicide against Magnaporthe oryzae.

A facile asymmetric synthesis of (s)-14-methyl-1-octadecene, the sex pheromone of the peach leafminer moth.

An asymmetric synthesis of 14-methyl-1-octadecene, the sex pheromone of the peach leafminer moth has been achieved. The target molecule was synthesized in six linear steps and in 30.3% overall yield from commercially available hexanoyl chloride, (S)-4-benzyloxazolidin-2-one and 1,9-nonanediol. The hexanoyl chloride was connected with (S)-4-benzyloxazolidin-2-one, and with the induction of the chiral oxazolidinone auxiliary, after chiral methylation, LAH reduction and then tosylation gave the chiral key intermediate 5 in high stereoselectivity. 1,9-Nonanediol, was selectively brominated, THP protected and subjected to Li2CuCl4-mediated C-C coupling to afford a C12 intermediate. The target molecule, (S)-14-methyl-1-octadecene, was obtained after the two parts were subjected to a second Li2CuCl4-mediated C-C coupling. Our synthetic approach represents the first time a substrate-control asymmetric synthesis of (S)-14-methyl-1-octadecene has been reported.

Thiophene-functionalized octupolar triindoles: synthesis and photophysical properties.

Two thiophene-functionalized octupolar triindole molecules were synthesized through Suzuki and Sonogashira cross-coupling reactions. Their photophysical and electrochemical properties were explored. The spectroscopic data demonstrate that triindole is an excellent rich electronic central donor for building octupolar optoelectronic molecules and possesses excellent luminescent properties. Thiophenylethynyl substituted triindole compound 3,8,13-tri(2-thiophenylethynyl)-5,10,15-tributyltriindole forms an intermolecular aggregation induced by π-π stacking from the rigid coplanar molecular scaffold. The redox curves and results of theoretical calculation imply that the two compounds have low ionization potential and low E(1/2 oxd), which may be originated from the high electronic density of both triindole and thiophene groups.

An improved synthesis of 1,2-diarylethanols under conventional heating and ultrasound irradiation.

A simple and efficient synthesis of 1,2-diarylethanols has been developed. The procedure involved the reaction between a variety of toluene derivatives and aryl aldehydes under conventional heating and ultrasound irradiation. This procedure possesses several advantages such as operational simplicity, high yield, safety and environment benignancy. Ultrasound was proved to be very helpful to the reaction, markedly improving the yield and the reaction rate.

2-Meth-oxy-4-methyl-1-[1-(phenyl-sulfon-yl)propan-2-yl]benzene.

The title mol-ecule, C(17)H(20)O(3)S, displays a U-shaped structure; the two benzene rings are nearly parallel and partially overlapped to each other, the dihedral angle and centroid-to-centroid distance being 15.0 (2)° and 3.723 (2) Å. In the crystal, weak inter-molecular C-H⋯O hydrogen bonds link the mol-ecules, forming supra-molecular chains running along the a axis.

A short synthesis of bisabolane sesquiterpenes.

A facile total synthesis of three members of the bisabolane sesquiterpene family, namely (±)-curcumene, (±)-xanthorrhizol and (±)-curcuhydroquinone had been achieved in high overall yield. The synthesis used bromobenzene derivatives as starting materials. The halogen-lithium exchange followed by addition of isoprenylacetone and reduction of the obtained carbinols are the key steps of the synthetic pathway. This synthetic approach provides a new route to the bisabolane sesquiterpenes.

3,4-Bis(4-bromo-phen-yl)-N-phenyl-maleimide.

In the title mol-ecule, C(22)H(13)Br(2)NO(2), the three benzene rings are arranged in a propeller-like fashion around the central malemide ring, making dihedral angles of 48.2 (4), 30.2 (4) and 34.8 (4)° with the malemide ring. The C-C single-bond lengths connecting benzene groups and maleimide are significantly shorter [C-C = 1.468 (9) and 1.478 (9) Å] than a typical Csp(3)-Csp(3) single bond, indicating partial conjugation between the benzene and the mal-eimide. A weak non-classical C-H⋯O hydrogen bond helps to stabilize the crystal structure.

2-(4-Methyl-phen-yl)-1-(phenyl-sulfon-yl)propan-2-ol.

The title compound, C(16)H(18)O(3)S, features a U-shape mol-ecular structure with a dihedral angle between the terminal benzene rings of 20.8 (1)°. An intra-molecular O-H⋯O hydrogen bond helps to stabilize the mol-ecular structure. Inter-molecular classical O-H⋯O and weak C-H⋯O hydrogen bonding is present in the crystal structure.

4-[4-(1H-Tetra-zol-5-yl)phen-oxy]benzaldehyde.

The asymmetric unit of the title compound, C(14)H(10)N(4)O(2), contains two independent mol-ecules with similar structures. In one mol-ecule, the tetra-zole ring is oriented at dihedral angles of 17.71 (16) and 57.13 (17)°, respectively, to the central benzene ring and the terminal benzene ring; in the other mol-ecule, the corresponding dihedral angles are 16.46 (18) and 75.87 (18)°. Inter-molecular N-H⋯N hydrogen bonds and weak C-H⋯O and C-H⋯N hydrogen bonds occur in the crystal structure.

2,4-Dinitro-1-phenoxy-benzene.

The title compound, C(12)H(8)N(2)O(5), was obtained by the reaction of 1-chloro-2,4-dinitro-benzene and phenol in the presence of potassium carbonate. The nitro-substituted benzene ring lies on a mirror plane, with one NO(2) group in the same plane and the other disordered across this plane. The phenoxy-benzene unit is placed perpendicular to this mirror, resulting in an exact orthogonal relationship between the phenyl and benzene rings in the mol-ecule. The crystal packing exhibits no significantly short inter-molecular contacts.

Synthesis of a diamino substituted terphenyldivinyl chromophore.

(E,E)-1,4-bis(4'-aminostyryl)-2,5-bis(octyloxy)-benzene (6) and its derivative (E,E)-1,4-bis(4'-acetamidostyryl)-2,5-bis(octyloxy)-benzene (7) were synthesized and characterized after alkylation, bromomethylation, Horner-Emmons reaction and reduction from hydroquinone. In order to gain more molecular electronic data, HOMO and LUMO of compound 6 have been calculated by Gaussian 03 W.