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The first example of Cu-promoted cyclization of α-amino nitrile-tethered enynes incorporating an electron-deficient alkene component is described. A wide range of functionalized 3-azabicyclo[4.1.0]hepta-2,4-dienes and 4,5-dihydro-3H-azepines were prepared efficiently in a controllable manner. Moreover, the diverse cascade process enables efficient incorporation of tertiary amine moieties under mild reaction conditions. A possible reaction pathway is proposed on the basis of a series of control experiments.

A novel cinchona-alkaloid-derived organocatalyst has been developed to catalyze the asymmetric regioselective [3+2] cycloaddition of 3-isothiocyanato oxindoles with dibenzylidene ketones. A series of spirooxindole enols could be obtained in high yields with good-to-excellent diastereo- and enantioselectivities.

The 1,4-diazabicyclo[2.2.2]octane (DABCO) catalyzed divergent [3+2] annulation of C,N-cyclic azomethine imines with δ-acetoxyallenoates was developed; 5,6-dihydropyrazolo[5,1-a]isoquinolines and ethyl (Z)-3-acetoxy-3-tosylpent-4-enoates were afforded in moderate to good yields in a one-pot manner under mild conditions. This annulation reaction provides a highly efficient method to construct dinitrogen-fused heterocycles and ethyl (Z)-3-acetoxy-3-tosylpent-4-enoates at the same time.

A novel and convenient palladium-initiated radical cascade stereoselective iodofluoroalkylation/cycloisomerization of ene-vinylidenecyclopropanes with fluoroalkyl iodides has been developed. The reaction proceeds under mild reaction conditions with high atom economy and stereoselectivity, thereby allowing an efficient access to a variety of difluoromethylated or perfluoroalkylated pyrrolidines tethered with an alkyl iodide. Two plausible radical pathways for the transformation have been proposed on the basis of the results of control experiments and previous reports, which in one case it was thought that palladium(0) was an initiator rather than a catalyst.

An effective synthetic protocol for structurally diverse 4-acyloxy-1,2-dihydroquinoline compounds has been accomplished by a gold(I)-catalyzed tandem [3,3]-rearrangement and intramolecular hydroamination of propargylic esters, affording the desired products in good yields. Moreover, the asymmetric variant of this cyclization has also been achieved using a chiral nitrogen acyclic carbene (NAC) gold(I) complex. These products have application in the enantioselective synthesis of an aromatase inhibitor within three simple steps.

The highly enantioselective synthesis of dihydroisoquinoline derivatives from aromatic sulfonated imines tethered with an alkyne moiety, through a one-pot asymmetric relay catalysis of chiral-phosphine and gold catalysts, is reported. Enantiomerically enriched dihydroisoquinoline derivatives were afforded in good yields and good-to-excellent ee values under mild conditions, based on the asymmetric aza-Morita-Baylis-Hillman reaction. Dihydroisoquinoline derivatives containing two chiral centers were also synthesized through further transformations.

On the basis of asymmetric regioselective [3+2] or [3+2]/[4+2] cascade reaction of 3-isothiocyanato oxindoles with C=C and C=N bonds of α,β-unsaturated methanesulfonamides, diversified S-containing heterocyclic spirooxindole derivatives could be obtained in high yields along with good to excellent diastereo- and enantioselectivities under mild conditions in the presence of cinchona alkaloid-derived organocatalysts.

A novel and efficient synthetic protocol to access furoquinoline and thienoquinoline derivatives is presented.

A variety of axial chiral NHC-oxazoline gold(I) complexes are synthesized and combined with Selectfluor in situ to catalyze the oxidative cycloaddition reaction of enynone and alkenes with air as green oxidant.

A novel iron(III)-catalyzed intramolecular cycloisomerization of acetal-vinylidenecyclopropanes to afford a series of halogenated 1,2-disubstituted cyclobutenes tethered with a tetrahydropyrrole has been developed. The reaction is thought to proceed through a formal iron-catalyzed Prins cyclization followed by a ring-enlarging rearrangement of the methylenecyclopropane carbocation. The present protocol provides an alternative route to functionalized disubstituted cyclobutenes and the corresponding products could be successfully transformed into eight-membered oxacyclic products.

Title compounds are regioselectively synthesized by this new phosphine-catalyzed [4 + 1] annulation of Morita—Baylis—Hillman carbonates with oxindole-derived α,β-unsaturated imines.

A novel cinchona alkaloid derived amine catalyzes the [3 + 2] cycloaddition of oxindoles with 2-butenedioc acid esters to produce spirooxindoles with high diastereo-and enantioselectivity.

The title reaction is investigated with isatins, various types of electron-deficient alkenes derived from pyrrole structures and L-proline.

The catalytic asymmetric [3+2] cycloaddition of (3-isothiocyanato)oxindoles with azodicarboxylates has been explored in the presence of (DHQD)2PHAL. It affords spirooxindoles having two heterocycles at their C3′-position in excellent yields, with high enantioselectivities, and under mild conditions within 5 min. Moreover, another spirooxindole derived from the reaction of (3-isothiocyanato)oxindole with two molecules of azodicarboxylate could also be formed in excellent yields with the same high enantioselectivities under the standard conditions.

Great progress has been made in developing of homogeneous Au-catalyzed reactions in the past decade. The unique versatility and efficiency of gold complexes have been obtained including carbene ligated gold complexes. Due to the special linear coordination mode of gold(I) complex, Au catalyzed asymmetric reactions have become a huge challenge. Chiral carbene–gold complexes also have been applied in asymmetric reactions. Major breakthrough in this field has been obtained by the Toste group recently and more are expected in the future. This digest, by highlighting recent works, aims to make further progress in this fascinating research field.

An AuI/AuIII catalytic system was found to be effective for the cascade oxidative arylation and cyclization of allenoates with arylboronic acids to give the corresponding cyclic adducts in moderate yields. This reaction system constitutes a new method for the synthesis of β-aryl-γ-butenolides under mild conditions. Based on the previous mechanistic studies, a proposed AuI/AuIII redox catalytic cycle has been outlined.

The reactions are catalyzed by a novel Cinchona alkaloid-derived organocatalyst and different spirocyclic products are obtained depending on the reaction conditions and the ratios of reagents.

The carbazoles are obtained either through 1,2-alkyl migration of the metal carbene intermediates or a Wagner-Meerwein-type 1,2-alkyl shift or through ring-opening of the cyclopropyl group by nucleophilic attack of water or an alcohol.

A novel Au(I)-catalyzed 6-endo-dig cyclization of 1,1-bis(indolyl)-5-alkynes (I) and (III) is developed to give bis(indole) alkaloid analogues through a pseudo 1,5-migration of an indole moiety.

A facile protocol for preparation of bicyclo[4.2.0] heterocycles containing a nitrogen atom is developed starting from allene-alkylidenecyclopropanes.

A series of novel N-heterocyclic carbene-oxazoline ligands were synthesized in six steps. Palladium complexes were obtained by deprotonation of the benzimidazole salts and subsequent ligation with Pd(OAc)2 in THF. Different types of cyclic bis- and tetrapalladium complexes were achieved by modifying substituent of oxazoline group. The structures of these palladium complexes were characterized by NMR and X-ray diffraction analysis. Catalytic properties of these Pd-complexes were tested by Suzuki–Miyaura cross-coupling reaction.

Recent developments on Pd complex-catalyzed asymmetric additions in the last five years have been presented in this context. As can be seen from this paper, lots of Pd complex-catalyzed asymmetric reactions have been reported in last five years. The Pd-catalyzed asymmetric additions of CX bonds (X = C, O, N) with various nucleophiles including boronic acids are very efficient and highly stereoselective under mild conditions. These type reactions have been developed into well-established methods for the stereoselective construction of carbon–carbon and carbon–heteroatom bonds in organic synthesis.

Different nitrogen-containing Lewis bases catalyzed reactions of highly reactive allenyl acetates with isatin-derived oximes afforded the corresponding oxime ethers or nitrone derivatives in good to high yields with high regio- and stereoselectivities.

A highly regio- and stereoselective synthesis of pyrazolidine analogues by the use of N,N′-cyclic or C,N-cyclic azomethine imines with two different trifluoromethyl-containing olefins has been developed. The method affords highly functionalized trifluoromethyl-containing pyrazolidine analogues in excellent yields with high diastereoselectivities under mild conditions.

Bisphosphine compounds have a wide range of applications. In this paper, we reported that bisphosphine compounds could be prepared in moderate to good yields from dialkyl acylphosphonates under mild conditions in the presence of phenyldioxaborolane and potassium hydroxide via a C–P bond cleavage and a subsequent 1,2-migration of phosphoryl group.

Efficient methods to prepare phosphorous compounds using Ph2PI, generated from the corresponding chloride, as multifunctional reagent are described.

The novel complex (NHCPT) along with AgBF4 is a highly efficient system for the title reaction.

Chiral C2-symmetric N-heterocyclic carbene (NHC) palladium diaquo complexes 5a–c and the chiral C2-symmetric NHC-palladium complexes 5d and 5e prepared from (R)-BINAM or H8-(R)-BINAM could be used as the catalysts for the enantioselective arylation of arylaldehydes with arylboronic acids in which NHC-Pd complex 5a was found to be fairly effective in this reaction to give the corresponding adducts in moderate enantioselectivities along with moderate to good yields.

The Pd compounds PHC and PNC promote efficiently the addition of arylboronic acids (II) to dihydropyridones and other cyclic enones.

The chiral binaphthylthiophosphoramide L1 prepared from the reaction of O,O-diphenyl chlorothiophosphate with (R)-(+)-N-ethyl-1,1'-bi-naphthyl-2,2'-diamine was used as a catalytic chiral ligand in the copper(II) trifluoromethanesulfonate-promoted asymmetric addition of diethylzinc to di-phenylphosphinoyl-imines to give the corresponding adducts in 90-98% ee and good yields under mild conditions.

A novel Pd(II)–NHC complex, which has a ‘normal’ cis-chelating, bidentate structure is fairly effective in Suzuki and Heck-type cross-coupling reaction to give the products in good to excellent yields in most cases.

Axially chiral P,S-heterodonor ligand L1 is effective in the asymmetric allylic substitution of 1,3-diphenylpropenyl acetate with dimethyl malonate. its bidentate coordination pattern to a I'd metal center with both P and S atoms has been unambiguously established by X-ray diffraction and NMR spectroscopic analyses. Herein, we further disclose that axially chiral S,S-heterodonor ligands L2-L4 are also effective in the same reaction to give the allylic alkylation product in moderate to good ee. However, the corresponding S,O-heterodonor ligands are not as effective as the corresponding P,S- or S,S-heterodonor ligands in the same asymmetric reaction. (C) 2004 Elsevier Ltd. All rights reserved.

The photodissociation of HCl(ad) and HI(ad) on Xe/Ag(111) and Xe/K/Ag(111) surfaces at 248, 308, and 350 nm has been studied by measuring the time-of-flight spectra of H atoms recoiling from the surface. In each case, HCl(ad) and HI(ad), the lower work function metal gave photodissociation out to much longer wavelengths, indicative of a charge-transfer mechanism. For HCl(ad) on Xe/K/Ag(111) the photoinduced charge-transfer dissociation occurred at photon energies well below the bond dissociation energy, ruling out direct dissociation of the adsorbate.