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This paper proposes a lead zirconate titanate (PZT) thick-film piezoelectric microstator based on a high-performance PZT thick film fabricated by electrohydrodynamic jet (E-jet) printing. The PZT thick film element was printed directly on the elastic body from a PZT composite slurry to form the piezoelectric microstator. This fabrication process does not require conventional machining techniques such as thinning, bonding, and etching, and can be compatible with microelectromechanical systems (MEMS) technology. The printed PZT thick-film element exhibited compact and uniform features. The thick-film microstator produced a travelling wave with an amplitude of 345 nm, and the mechanical quality factor was found to be 736. The combination of E-jet printing and PZT thick-film technology simplified the manufacturing process and enhanced the performance of the piezoelectric stator, enabling the fabrication of a unique MEMS rotary ultrasonic motor device.

This paper presents a bi-stable mechanism, which mainly consists of a suspended mass, a spacer and a bottom plate. Electromagnetic actuation is used for switching between two states (i.e. ‘On/Off’ state). The actuation is achieved via permanent magnet (PM) on the suspended mass and micro-coils embedded in the bottom plate. Different from spiral coil and central core in conventional design, micro-coils in this paper integrate Cu and Ni together as a whole, acting as both coil and ferromagnetic core. This integration simplifies the fabrication into one-mask process. Furthermore, chessboard patterned PM is utilized with Cu-Ni integrated micro-coils to generate enhanced force density. The bi-stable mechanism is designed, fabricated and experimentally characterized. Total size of this mechanism is 16 × 14 × 2 mm3. No power is needed for holding either of the state. Switching processes (both ‘On’ to ‘Off’ and ‘Off’ to ‘On’) can be realized with external acceleration of 24 G (gravity) and 37 G, respectively. Furthermore, resetting (i.e. ‘On’ to ‘Off’) can also be accomplished with 1.5 A current input.

Dynamic performance is one of the most critical factors in many MEMS products, such as micro accelerometers, vibratory gyroscopes, micro deformable mirror, etc. Essentially, the dynamic behavior is totally determined by two factors: the internal factor, the stiffness of structure and the external factor, the damping of environment. In this paper both factors are analyzed accurately and a theoretical dynamic model of parallel-plate actuators is presented. The stiffness of the structure, i.e. the spring constant k of the suspension beam that supports the moving plate of the actuator, is achieved by many accurate experimental tests. The damping of environment, referring to the squeeze film damping coefficient c in parallel-plate actuators, is analyzed by calculation and FEA simulation. Further, we consider c a linear function of the actuator displacement, but not a constant value. This treatment greatly improves the accuracy of the dynamic model and could be applied in parallel-plate actuators with large displacement. Dynamic behaviors of the actuators under squeeze film damping, such as natural frequency, response time and bandwidth, are predicted based on the model. Three kinds of parallel-plate actuators are designed and fabricated using a surface micromachining process to verify the estimation of the presented theoretical model and experimental test results have showed good consistency with the theoretical analysis. The dynamic model proposed in this paper could be broadly applied in the MEMS/NEMS systems.

Presented in this paper is a bi-directional out-of-plane actuator which combines the merits of the electrostatic repulsive principle and the electrostatic attractive principle. By taking advantage of the electrostatic repulsive mode, the common "pull-in" instability can be lessened to enlarge the displacement, and by applying the electrostatic attractive mode, the out-of-plane displacement is further enlarged. The implications of changing the actuator's physical dimensions are discussed, along with the two-layer polysilicon surface microfabrication process used to fabricate such an actuator. The static characteristics of the out-of-plane displacement versus the voltage of both modes are tested, and displacements of 1.4 mu m and 0.63 mu m are obtained at 130 V and 15 V, respectively. Therefore, a total stroke of 2.03 mu m is achieved, more than 3 fold that of the electrostatic attractive mode, making this actuator useful in optical Micro-Electro-Mechanical Systems (MEMS) and Radio Frequency (RF) MEMS applications.

2H-1,2,3-Diazaphospholes 3a—3h were prepared from various ketone acylhydrazones and phosphorus trichloride in the presence of triethylamine. Compounds 3 underwent feasible hetero-Diels-Alder reactions with cyclopentadiene to afford the respective anellated [1,2,3]diazaphospholes 4a–4d as well as 4a'—d.″ in moderate yields. The endo rule in the reaction was observed under kinetic control conditions.

Based on the structure of Go6976, a known isoform-selective protein kinase C inhibitor, a benzofuran analogue (1) was designed. This analogue was synthesized by coupling of benzofuran 3-acetic acid and 8-oxo-tryptamine and subsequent intramolecular Dieckmann condensation, alkylation, oxidative photocydization and cyanation reaction of mesylate.

2,3-Allenols were prepared conveniently from the reduction reaction of 2, 3-allenoates with DIBAL-H (Diisobutylaluminum hydride) in toluene. A dramatic solvent effect was observed for this reaction.

A practical procedure for palladium catalyzed Suzuki cross-coupling reaction of arylboronic acids with aryl halides, including aryl chlorides in molten tetra-n-butylammonium bromide (TBAB) was developed. The reaction exhibits high efficiency and functional group tolerance. The recovery of the catalyst and molten n-Bu4NBr was also investigated.

β-Cyclodextrin (β-CD)-ended linear poly(N-isopropylacrylamide) (β-CD-PNIPAM) and Frechet-type benzyl ether dendron with an azobenzene group (Gx-Azo) at the apex site form noncovalently connected amphiphiles (NCCAs) by inclusion complexation between the azo group and β-CD. The NCCAs self-assemble into vesicles in water. Optical switching of the assembly and disassembly is realized by alternating visible and UV irradiation, which causes the isomerization of the azo groups and their consequent complexation and decomplexation with β-CD. The structure and morphology of the vesicles were characterized by dynamic light scattering (DLS), static light scattering (SLS), SEM, TEM, and AFM. These photoresponsive vesicles can further respond to heat stimuli resulting in reversible aggregation and disaggregation of the vesicles.

An efficient palladium-catalyzed amination of aryl halides with amines, using rac-P-Phos as the ancillary ligand and Pd(OAc)2 as the palladium source is developed. The ligand and all of the synthetic intermediates are stable to air and moisture, allowing the easy handling. The catalyst system performed well for a large number of different substrate combinations in 80–110°C to furnish aromatic amines in high yields.

An efficient synthesis of novel O-protected isotetronic acids is described. The method relies on DBU (1,8-diazabicyclo[5.4.0]-undec-7-ene) and triethylamine triggered homo-aldol reactions of 2-oxocarboxylic esters, followed by successful ring closure via lactonization and O-protection with various electrophiles. The unprotected isotetronic acids were also achieved with moderate to high yields if the free-OH group were pre-capped by the silylation agent TMSCl. All the three reaction steps were conducted in a sequential manner, without isolation of any intermediates.

The sequential homoaldol-lactonization-alkylation/acylation- reactions of ethyl pyruvate with a variety of halides were achieved by using DBU along with Et 3 N as the base. The protocol provides an expedient one-pot synthesis of O-protected isotetronic acid derivatives. The high-yielding synthesis of an unprotected isotetronic acid is also described.

A soluble polymer (MeO-PEG) supported biphenylbisphosphine (BIPHEP)-Ru/chiral diamine (1,2-diphenylethylenediamine) complex, in which the polymer is attached to the two phenyl rings of BIPHEP ligand, has been prepared, and shown to be highly active with good enantioselectivity for the catalyzed asymmetric hydrogenation of unfunctionalized aromatic ketones. The derived chiral ruthenium complex 5 proved to be stable in air allowing facile catalyst recycling. Especially for 4′- tert -butyl-acetophenone and 1-acetonaphthone, excellent ee values up to 96.5% and 95.9% have been obtained which are comparable to or even higher than the enantioselectivity achieved with 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl-Ru-DPEN catalyst under similar conditions.

The novel tricyclic heterocycles of 4,5-dihydro[1,2,4]triazolo[3,2- D][1,5]benzoxazepine derivatives were prepared by the cycloaddition of the corresponding bicyclic cationic 1,3-dipoles, which were easily generated from the azoacetates by reaction with AlCl 3 as a Lewis acid, to the triple bond of nitriles along with the consecutive ring expansion. The formation of products deviating from the normal reaction aptitudes was observed and the mechanistic aspects are discussed herein. Crystal diffraction analysis for two of the products unequivocally established the respective structures proposed.

Derivatives of two new heterocyclic systems, namely furo[3,2-c][1,2,4]triazolo[1,5-a]azepinium salts and furo[2,3-f][1,2,4]triazolo[1,5-a]azepinium picrates, were synthesized from bicyclic azo compounds and nitriles in the presence of antimony pentachloride or aluminum chloride. The crystal diffraction analysis of an example product is reported and confirms the structure.

The preparation of a novel chiral 2,2'-bis(MeO-PEG-supported)-6,6'-bis(diphenylphosphanyl)biphenyl (MeO-PEG-Biphep) ligand is described. The derived ruthenium complex catalyzes the hydrogenation of β-ketoesters in up to 99% yield and 99% ee under atmospheric pressure. The accelerating effects exerted by the PEG linkage are dramatic when compared to the unsupported analogue, MeO-Biphep-RuBr 2 . Furthermore, the catalyst can be recovered easily and the recycled catalysts were shown to maintain their efficiency in two consecutive runs, albeit with declining activity. One of the products, (S)-ethyl-3-hydroxy-3-phenylpropanoate, is useful in the preparation of (5)-fluoxetine.

A series of 2-acyl-2H-1,2,3-diazaphospholes 3 underwent ready 1,3-dipolar cycloaddition reactions with 9-diazofluorenes as the 1,3-dipole, yielding the respective bicyclic phosphiranes 5 or trimers 7 depending on the reaction conditions employed. The reaction is believed to proceed via the formation of the [3+2]-cycloaddition adducts followed by elimination of nitrogen from the cyclic azo moiety. In the case of 3c, the phosphatetraazabicyclooctadiene compound 6 has been isolated with no loss of nitrogen. Likewise, the dipolar cycloaddition reaction of diphenyldiazomethane with the >CP- moiety as the 1,3-dipolarophile gave phosphadiazabicyclohexenes 8 in 32–68% yields.

A synthetic approach to the previously unknown thieno[2,3-f][1,2,4]triazolo[1,5-a]azepine derivatives was efficient-ly accomplished by cycloaddition of the bicyclic 1-aza-2-azoniaallene salts 6, derived from 6,7-dihydrobenzo[b]thiophen-4(5H)-one hydrazones 4, to the triple bond of nitriles, followed by ring enlargement. The X-ray crystal diffraction analysis of the picrate 10a provided affirmative proof for the structural assignment made.

Noncentrosymmetric y-type alternating multilayers of NMOB/CdA (NMOB stands for 2-nitro-5-(N-methyl-N-octadecyl) aminobenzoic acid) were prepared for use in the testing of Langmuir–Blodgett (LB) films in waveguide-type second-harmonic-generation (SHG) devices. After using two methods to improve the film quality, the LB films exhibited a near-quadratic dependence of the SHG intensity on the number of film layers. A film consisting of 115 bilayers of NMOB/AA (AA stands for arachidonic acid) was fabricated which met Cerenkov phase-matching conditions, and SHG from this waveguide pumped at 1064 nm was measured. Preliminary results show that the improved multilayer LB films are suitable for fabricating waveguides with second-order nonlinear optical properties.

The synthesis of the tetrakis{2-[1-(2,4,6-trichlorophenyl)-1H-1,2,4-triazol-5-yl]ethoxymethyl}methane derivatives 5a–c, 6 and 7, and the nitrotris{2-[1-(2,4,6-trichlorophenyl)-1H-1,2,4-triazol-5-yl]ethyl}methane derivatives 9a–c, 10 and the picrate 11 has been accomplished by reaction of the 1-aza-2-azoniaallene salts 3 with either the aliphatic tetranitrile 1 or trinitrile 8, in high yields; the X-ray crystal structure of 5b is also reported.

In the presence of mercuric chloride, the reactions of esters with allyl bromide and metallic dysprosium in anhydrous THF give diallyl alkyl carbinols in good yields. When γ-butyrolactone is used as the substrate, the corresponding product is 4-allyl-6-heptene-1, 4-diol.

(1-Chloro-2-trifluoromethylcyclohexyl)azo compounds 3a-d, prepared by oxidation of the hydrazones 2a-d of 2-trifluo-romethylcyclohexanone (1) with a slightly excess amount of tertbutyl hypochlorite, react with antimony pentachloride and a nitrite to afford the respective 2,3-disubstituted-9-trifluoromethyl-6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[1,5-a]azepinium hexachloroantimonates 6a-j. The reaction mechanism comprises of the initial cycloaddition of the in situ generated 1-aza-2-azoniaallene salts 4 to the triple bond of nitrile, giving the spiro-substituted 5a-j, followed by rearrangement and concomitant ring enlargement. From 3a-c where R 1 aryl, the salts 6a-h are isolated in high yields. However, if ethyl (1-chloro-2-trifluoromethyl)azocarboxylate (3d) is employed, the neutral N(3)-unsubstituted analogues 7a and 7b are obtained and after usual basic work-up, are converted to picrates 8a and 8b respectively. For one compound 6f. the X-ray diffraction analysis has been carried out in order to confirm the structural assignment. A practical modified procedure for preparation of the crucial starting ketone 1 is also described.

An expedient synthesis of neutral [1,2,4]triazolo[3,2-d][1,5]-benzoxazepines 6a–e and their chalcogen analogues 6f–i was accomplished via cycloaddition of the heterocumulene cations (3a,b), generated sequentially by action of chroman-4-one as well as thiochroman-4-one ethoxy carbonylhydrazones (1a,b) with t-BuOCl and SbCl5, to the triple bond of nitriles and concurring ring enlargement and hydrolytic removal of the N(1)-ethoxycarbonyl group. The oily final products were characterized as their picrates.

The reaction of dichloroborane BHCl2 with 3,3,3-trifluoro-prop-1-ene (TFP), and propene have been studied using B3LYP method with 6–31G+ basis set. Based on the calculations, all transition structures have parallelogram-like H-B-C-C four-center geometry with small deformations. The introduction of fluorine atoms changes the proportions of hydroborational products and reverses the regioselectivity.

Ethyl (l,l,l-trifluoro-2-propylidene)carbazate is converted with tert-butyl hypochlorite to the 2-chloro-l,l,l-trifluoro-2-propyl azo compound 2, which reacts with antimony pentachloride to produce the trifluoromethylated 1-aza-2-azoniaallene salt 3 as a highly reactive intermediate. The cation 3 is employed as a CF3-containing synthon for the preparation of the 5-trifluoromethylated 1H-1,2,4-triazoliumpicrates 6a-e.

The detailed dissociation mechanism of diborane (B 2 H 6 ) in dimethyl sulfide (Me 2 S) media has been studied at the levels of B3LYP/6-311G**//B3LYP/6-31G* and B3PW91/6-311G**//B3PW91/6-31G*. All the calculations predict a two-step mechanism for the dissociation and only one H-bridge bond is broken in each. In comparison with the dissociation of B 2 H 6 in vacuum or in hydrocarbon media, the participation of Me 2 S significantly lowers the activation barriers in the process. The barriers are even more lowered when solvent effect is embraced.

A peroxide monomer, 4,4′-divinyl benzoyl peroxide (DVBPO), was synthesized. Bulk copolymerization of DVBPO with methyl methacrylate (MMA) was initiated by di(2-ethyl hexyl)peroxy carbonate (EHP). DSC curves and the appearance of crosslinking of the product showed that DVBPO can copolymerize with MMA. The grafting copolymerization of butyl acrylate (BA) onto the copolymer was performed. The grafting efficiency (GE), determined by Soxhlet extraction, was high.

Two optically pure derivatives of α-cedrene — (1R,2R,5S,7R,8R)- 8-hydroxy-9-cedranone 2 and (lR,2R,5S,7R,8R,9S)-9-amino-8-hydroxycedrane 4 were prepared conveniently. An X-ray structural analysis of 2 was performed indicating that the hydroxycedranone exists as dimer due to one hydrogen bond in solid state.

100 bilayers 2-nitro-5-(N-methyl-N-octadecyl)aminobenzoic acid (NMOB) and cadmium arachidate (CdA) alternated Langmuir–Blodgett (LB) film was fabricated. The thickness of NMOB monolayer is 2.85 nm measured by small angle X-ray diffraction. It shows that NMOB molecule stands vertically in the alternated film. A DFT method, B3LYP, was used to calculate the energies of various conformations of NMOB with 4-31G* basis set. The computational results show that the tilted conformation is the most stable and the energy difference between this conformation and the vertical one is 31 kJ/mol. The refractive indices of NMOB/CdA alternated films were also determined at different wavelengths by waveguide measurement.

Homologation of cedranediol boronic esters 1, RBO,C15H,4l with (dichloromethyl)lithium resulted in the formation of (αR)-α-chloro boronic esters 3, RCHCIBO2C15H24, consistently yielding (R)/(S)ratios over 25:1. The absolute configuration of cedranediol (R)-1-chloro-1-phenylmethylboronate 3dR was determined by X-ray diffraction. The distortion of the five-membered 1,3,2-dioxaborolane ring of 3dR from planarity was found. The reason why the cedranediol boronic esters are prone to hydrolysis has been discussed.

(-)-Cedranediol boronic esters 4, a series of asymmetric homologation reagents were prepared from a new chiral director (-)-cedranediol 3 and boronic acids. (-)-Cedranediol 3 was easily synthesized by the dihydroxylation of (-)-α-cedrene 2 with OsO4. A more convenient method for the preparation of boronic acids was developed as well.

A 19 element segmented MEMS deformable mirror(DM) based on electrostatic repulsive-force actuator is proposed and fabricated using a commercial surface micromachining process PolyMUMPs. Impacts of different sizes of actuator on DM’s characterizations such as stroke, work bandwidth, driving voltage and fill factor are analyzed and optimized. An analytical analysis combined numerical simulation has been performed on the deformation of repulsive flexural beam actuator regarding actuator size and boundary condition. These analytic insights could provide guidelines for future MEMS DMs optimum design. A maximum stroke of the fabricated DM is 2.6μm, is larger than 2μm for the sacrificial layer thickness of PolyMUMPs. The preliminary aberration correction of the whole DM array is also analyzed. Compared to conventional MEMS DMs, this design demonstrates the advantage of large stroke over a standard surface micromachining fabrication process with a thin deposited layer, and it would expand the application of MEMS DMs in adaptive optics.

A new amphiphilic compound NMOB (2-nitro-5-(N-methyl-N-decosyl) aminobenzoic acid) with both good film forming property and high optical nonlinearity was synthesized for applications of Langmuir-Blodgett (LB) films in waveguide-type second harmonic generation (SHG) devices. The near-quadratic dependence of the SHG intensity on the bilayer number, the small angle X-ray diffraction (SAXD) patterns and the temporal stability of alternating CdA (cadmium arachidate)/NMOB multilayers confirmed their good film structures. We obtained the hyperpolarizability beta of NMOB of 6.3*10-50 C m3 V-2 (1.7*10-29 esu) at a fundamental wavelength of 0.064 mu m from transmitted SHG measurements which agreed with those deduced from our linear electro-optic (EO) modulated attenuated total reflection (ATR) spectra at 832 nm, 633 nm and 488 nm in order of magnitude. A resonant enhancement of the EO response near the absorption band in NMOB monolayers was observed for the first time.

[reaction: see text] Diaryl ethers have been prepared by direct coupling of phenols including those that bear a strong electron-attracting substituent to electron-deficient aryl halides through S(N)Ar-based addition reactions with assistance of microwave irradiation in high to excellent yields within 5-10 min. No catalysts were required under our conditions.

The mechanisms of cycloaddition reactions between 1-aza-2-azoniaallene cations 1 and acetylenes 2 have been investigated using the global electrophilicity and nucleophilicity of the corresponding reactants as global reactivity indexes defined within the conceptual density functional theory. The reactivity and regioselectivity of these reactions were predicted by analysis of the energies, geometries, and electronic nature of the transition state structures. The theoretical results revealed that the reaction features a tandem process: an ionic 1,3-dipolar cycloaddition to produce the cycloadducts 3 H-pyrazolium salts 3 followed by a [1,2]-shift affording the thermodynamically more stable adducts 4 or 5. The mechanism of the cycloaddition reactions can be described as an asynchronous concerted pathway with reverse electron demand. The model reaction has also been investigated at the QCISD/6-31++G(d,p) and CCSD(T)/6-31++G(d,p)//B3LYP/6-31++G(d,p) levels as well as by the DFT. The polarizable continuum model, at the B3LYP/6-31++G(d,p) level of theory, was used to study solvent effects on all the studied reactions. In solvent dichloromethane, all the initial cycloadducts 3 were obtained via direct ionic process as the result of the solvent effect. The consecutive [1,2]-shift reaction, in which intermediates 3 are rearranged to the five-membered heterocycles 4/5, is proved to be a kinetically controlled reaction, and the regioselectivity can be modulated by varying the migrant. The LOL function and RDG function based on localized electron analysis were used to analysis the covalent bond and noncovalent interactions in order to unravel the mechanism of the title reactions.

(-)-Cedranediol boronic esters 4, a series of asymmetric homologation reagents were prepared from a new chiral director (-)-cedranediol 3 and boronic acids. (-)-Cedranediol 3 was easily synthesized by the dihydroxylation of (-)-α-cedrene 2 with OsO4. A more convenient method for the preparation of boronic acids was developed as well.

Two optically pure derivatives of α-cedrene — (1R,2R,5S,7R,8R)- 8-hydroxy-9-cedranone 2 and (lR,2R,5S,7R,8R,9S)-9-amino-8-hydroxycedrane 4 were prepared conveniently. An X-ray structural analysis of 2 was performed indicating that the hydroxycedranone exists as dimer due to one hydrogen bond in solid state.

The title compound, 2,2′-(2,4,8,10-tetra­thia­spiro­[5.5]­undec­ane-3,9-diyl­idene)­bis­(propane­di­nitrile), C13H8N4S4, has been designed and synthesized for use as a potential new organic molecular electronic material. The spiro-annulated structure has twofold symmetry and is formed by two equal push–pull ethyl­ene units, with the cyclo­alkyl­thio groups as electron donors and the cyano groups as electron acceptors. The intermolecular S⋯N non-bonded separation within a layer in the lattice is 3.296 (6) A, indicating a strong intermolecular interaction between the cyano groups and the S atoms, while the S atoms in two neighbouring mol­ecules have a shortest S⋯S contact of 3.449 (3) A. In addition, attractive C—H⋯N and C—H⋯S interactions bridge adjacent mol­ecules either within a layer or between layers. In short, these four types of intermolecular interactions combine to form an extended three-dimensional network in the lattice, resulting in a highly ordered array of molecular packing.

(1-Chloro-2-trifluoromethylcyclohexyl)azo compounds 3a-d, prepared by oxidation of the hydrazones 2a-d of 2-trifluo-romethylcyclohexanone (1) with a slightly excess amount of tertbutyl hypochlorite, react with antimony pentachloride and a nitrite to afford the respective 2,3-disubstituted-9-trifluoromethyl-6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[1,5-a]azepinium hexachloroantimonates 6a-j. The reaction mechanism comprises of the initial cycloaddition of the in situ generated 1-aza-2-azoniaallene salts 4 to the triple bond of nitrile, giving the spiro-substituted 5a-j, followed by rearrangement and concomitant ring enlargement. From 3a-c where R 1 aryl, the salts 6a-h are isolated in high yields. However, if ethyl (1-chloro-2-trifluoromethyl)azocarboxylate (3d) is employed, the neutral N(3)-unsubstituted analogues 7a and 7b are obtained and after usual basic work-up, are converted to picrates 8a and 8b respectively. For one compound 6f. the X-ray diffraction analysis has been carried out in order to confirm the structural assignment. A practical modified procedure for preparation of the crucial starting ketone 1 is also described.

α-Pyrone derivatives were synthesized via the base catalyzed or promoted reaction of 1,2-allenyl ketones and electron-withdrawing group substituted acetates. The reaction was believed to proceed through a Michael addition C−C double-bond migration−lactonization process.

A stilbazium salt was synthesized and its second-order molecular polarizability was deduced to be 1.2×10 −27 esu. Measurements of second-harmonic generation and small-angle X-ray diffraction on Langmuir-Blodgett films of the stilbazium salt/arachide acid mixtures showed that the mixed compounds with molar ratios of 1:2 and 1:5 could form multilayers with large second- order optical nonlinearity. Second harmonic generation study on the alternate multilayers of stilbazium salt/arachide acid and arachidic acid showed that the second-harmonic signals were increasing monotonously up to 80 bilayers, but the increment was lower than the value predicted theoretically by the quadratic law. Possible reasons are discussed.

Ultrasonicated reactions of 1,1-dihaloolefins with lithium, magnesium or sodium in the presence of alkenes rapidly afford multisubstituted methylenecyclopropanes.

An efficient palladium-catalyzed amination of aryl halides with amines, using rac-P-Phos as the ancillary ligand and Pd(OAc)2 as the palladium source is developed. The ligand and all of the synthetic intermediates are stable to air and moisture, allowing the easy handling. The catalyst system performed well for a large number of different substrate combinations in 80–110°C to furnish aromatic amines in high yields.

The sequential homoaldol-lactonization-alkylation/acylation- reactions of ethyl pyruvate with a variety of halides were achieved by using DBU along with Et 3 N as the base. The protocol provides an expedient one-pot synthesis of O-protected isotetronic acid derivatives. The high-yielding synthesis of an unprotected isotetronic acid is also described.