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Tetrakis(triphenylphosphine)platinum in DMF was utilized as a mild catalyst for cross-coupling reactions of organoboronic acids with aryl iodides. The present reactions exhibited excellent group-selectivity where couplings of organoboronic acids 2a – e with 4-bromo-1-iodobenzene ( 4 ) give 4-arylbromobenzenes 5a – b and 4-alkenylbromobenzenes 5c – e in excellent yields.

Various 2-[6-en-1-ynyl]benzaldehydes and their analogues were successfully cyclized via Huisgen-type [3+2] cycloaddition to the tetracyclic platinum-carbene complex, which would subsequently undergo hydration to afford the tricyclic products in good yields with excellent stereoselectivities. This hydrative cyclization was also applied to the faveline synthesis.

We have developed an efficient method for the synthesis of 2,3-disubstituted indoles from alkyne iminoethers 1 that employs a domino process involving Ag-catalyzed condensation followed by a tandem Ag-induced cycloisomerization and 1,3-alkenyl shift to Ag-activated carbon. This methodology can be useful in regioselectively constructing 3-alkylated indoles, which are part of the structures of biologically active compounds and important alkaloids.

New, racemic, tricyclic trioxane alcohol 3 was designed and synthesized as a structurally simple analog of clinically useful, tetracyclic, antimalarial artemisinin. A series of 20 ester and ether derivatives of alcohol 3 were prepared easily, without destruction of the essential trioxane system. Chemical structure-antimalarial activity for each derivative was evaluated in vitro against chloroquine-resistant and chloroquine-sensitive Plasmodium falciparum parasites. Many of these derivatives were highly efficacious; carboxylate ester 9f, carbamate ester 10a, and sulfonate ester 12a had antimalarial potency similar to that of artemisinin, and carboxylate esters 9b and 9d, carbamate esters 10b and 10c, and phosphate esters 11a-c had antimalarial potency up to 7 times higher than that of artemisinin. Several of these most active analogs (e.g., carboxylate 9b and carbamates 10a and 10c) are stable crystalline solids, a feature of considerable practical value for any new drug candidate.

Atom-economical syntheses of isomeric 5-acetoxy-2-alkyl-2-cyclopentenones (2) and acetoxymethyl α-alkylallenones (3) have been described via Au-catalyzed hydrative rearrangement of 1,1-diethynylcarbinol acetates (1). In anhydrous condition, Au(I)-catalyzed [3,3]-rearrangement of 1 afforded the 3-alkynylallenyl acetate 4 in low yield. Treatment of 1 with Au(I) catalyst in wet CH2Cl2 produced either 2 or 3 as a major product depending on the temperature, reaction time, and catalyst loading. D has been proposed as an intermediate, which might be formed via Au(I)-induced internal oxacyclization of the intermediate 4 followed by chemoselective nucleophilic attack by the water molecule. Formation of 2 or 3 might be explained via sequential 1,3-dioxole ring opening and gold-promoted 5-endo-dig carbocyclization or simple protonation of the intermediate D, respectively.

2-Alkynyl-1-cycloalkenecarbaldehydes, in the presence of gold catalysts, undergo aurative cyclizationvia the 5-exo-dig mode to form Au-carbene intermediates which react with a double bond to form the corresponding cyclopropanes.

BF 3 ·OEt 2 in methylene chloride at 25°C for 2 hours or less is shown to be effective for easy conversion of tertiary alcohols into the corresponding thermodynamically most stable alkenes.

Oxidative cleavage of alkenyl esters and thether using Et 3 SiOOOH was found to be easier than oxidative cleavage of hydrocarbon alkenes, and Et 3 SiOOOH was successfully applied to very short syntheses of new, simple, and potent antimalarial trioxanes 6 and 8 . Triethylsilyl hydrotrioxide was successfully applied to syntheses of new antimalarial 1,2,4-trioxanes 6 8 .

2-Alkynyl-1-cycloalkenecarbaldehydes, in the presence of gold catalysts, undergo aurative cyclization via the 5-exo-dig mode to form Au-carbene intermediates which react with a double bond to form the corresponding cyclopropanes.

We discovered a new and highly convenient gold-catalyzed cyclization of alkyne-propargylic pivaloates leading to fused bicyclic compounds.

Since transition metal catalysis allows simultaneous formation of more than one bond in a single step operation with high selectivity, the exploitation of a model compound for nitrogen-containing polycyclic biologically active natural products has been a worthwhile contribution in synthetic and medicinal chemistry. Intramolecular hydroamidation of acetylenes, carbonylation of 2-alkylbenzenylamines, 1-aryl-3-hexen-1,5-diynes initiated by methoxide addition, fluoroarenes and nitriles via 1,2-arynes, nitroarylstannanes, radical dearomatization of benzene and hydrothermal reaction of o-phenylaniline, ullamann cross-coupling of 1-bromo-2-nitroarenes and 1,3dipolarcycloaddition of nonstabilized azomethine ylide and photocycloaddition of phthalimide anion to alkenes have been used to synthesize benzazepinone, phenanthridine and benzophenathridinone derivatives. However, these synthetic routes are often complicated and limited to only some substituents. Recently, we reported various cycloisomerization reactions with different unsaturated systems catalyzed by Au, Pt, Pd, and Rh. Our continued interest in the synthesis of polycyclic systems prompted us to develop the Rhcatalyzed cyclization of o-alkynylbenzaldehydes having a nitrile tether that produced tricyclic benzazepinones and benzophenanthridine derivatives via [3+2] and [4+2] cycloaddition via pyrylium intermediates as shown in Scheme 1. An initial study was tested with o-alkynylbenzaldehyde 1a in the presence of various late transition metal catalysts (Table 1). PtCl2 as a catalyst in refluxing 1,4-dioxane for 12 h converted 1a to give a mixture of products, which were separated by column chromatography to give 2,3-dihydrobenzo[e]cyclopenta[b]azepin-5(1H)-one (3a) in 50% yield along with the hydrated product 2a in 30% yield (entry 1). When this reaction was carried out in dry 1,4-dioxane in the presence of 4 A molecular sieves, the reaction was dramatically accelerated to give the product 3a in 59% yield still along with 2a in 10% yield (entry 2). We presumed that a trace amount of water in the reaction medium or in solvent might generate a nucleophile which could undergo hydration to the metal-activated triple bond followed by tautomerization to the corresponding ketoaldehyde 2a. It was observed that gold(III) bromide in 1,2-dichloroethane (EDC) hydrated 1a to afford 2a even at room temperature exclusively (entry 3). This might be understood by the high reactivity of gold catalyst or the poor reactivity of the nitrile group toward the pyrylium intermediate A. We tried the same reaction with different catalysts, such as AuCl3, AuCl(PPh3) with AgSbF6, and AgSbF6 itself, under dry reaction condtions, but led to hydration (entries 4-6). In fact, Zhu et al. reported that o-alkynylbenzaldehydes were hydrated in the presence of gold(+3) catalysts and trifluoroacetic acid to afford the corresponding ketoaldehyde. Finally, we found [Rh(COD)Cl]2 as an optimal catalyst for the present [3+2] cyclization of pyrylium intermediate, generated in situ with alkynophilic metal cations, with a pendent nitrile. Thus, when the substrate 1a in the presence of [Rh(COD)Cl]2 (10 mol%) in dry xylene containing 4 A molecular sieves was heated at 110 C for 12 h, the product 3a was isolated in 71% yield along with the ketoaldehyde 2a in 10% yield. With this promising result, we further examined this [3+2] cycloaddition with structural alteration in the tether (eq. 1-2). This paper is dedicated to Professor Sang Chul Shim at Kyungpook National University on the occasion of his honorable retirement. Scheme 1 Table 1. Optimization of intramolecular [3 + 2] cyclization-cycloaddition under various reaction conditions with 1a

We report a new and highly-convenient Au-catalyzed cyclization of alkyne propargylic acetates leading to 2,3-bis(alkylidene)cyclohexanones and their cycloadditions with a pendant dienophile.

Conjugated enynals anchored to cycloalkenes, in the presence of platinum catalysts, were cyclized to the corresponding [m,7,n]-tricarbocycles, which are valuable skeletons in biologically active natural products like taxoids.

We have discovered a new and highly convenient Ag-catalyzed intramolecular oxycyclization of alkynes, leading to bridged bicyclic ketals as four carbon synthetic building blocks.

By utilizing the facile formation of an imine from an -aldehyde and an amine, we have discovered a new and highly -efficient Pd-catalyzed cycloreduction of enediynals leading to the corresponding 2-(2-methylenecycloalkyl)pyrroles in good to excellent yields.

[structure: see text]. We have discovered a new method employing Pd-catalyzed cycloreduction of conjugated enynals 1 bearing an alkyne unit leading to the corresponding 2-(2-methylenecycloalkyl)-furans 2a-j and a related compound 7 in good to excellent yields.

[reaction: see text] A new and novel Au-catalyzed cycloisomerization of ynals bearing a pendant unsaturated bond leading to synthetically valuable [6.7.n]-tricyclic compounds were developed. This study strongly supports the intermediacy of [3 + 2] cycloaddition proposed by DFT calculation and provides an easy access to key skeletons found in a variety of natural products.

Pd-catalyzed cycloreduction of enediyne 3 successfully afforded the linear triquinane skeleton 4. Total synthesis of (′)-ceratopicanol was accomplished using additional eight-step transformations starting from 4.

The aim of this study was to synthesise pure enantiomers of potent antimalarial 1,2,4-trioxanes, which are related to the natural antimalarial artemisinin, and then to assay each against a panel of Plasmodium falciparum strains. The working hypothesis was that if the artemisinin derivatives interact with a specific protein-target site, then there should be stereoselective differences in their activity. In five different P. falciparum isolates, however, the trioxane enantiomers (+)-7 a, (-)-7 a and (+)-7 b, (-)-7 b, showed the same level of in vitro antiparasitic activity.

o-(1,6-Enynyl)benzaldehydes underwent a novel mode of cycloaddition using Rh(I)-precatalyst, via [3 + 2] cycloaddition of presumed dipolar carbonyl ylide intermediate generated by Rh-catalyst and the utility of this mechanistically intriguing enyne cyclization can be found in a number of polycyclic natural product skeletons.

In contrast to the ene behavior of allenes in Pauson–Khand reactions and other cyclization reactions, 1,6-allenynes undergo unprecedented carbocyclization followed by regioselective addition of organoboronic acids in the presence of Pd(OAc) 2 and tri- t -butyl phosphine under mild reaction conditions.

An efficient palladium-catalyzed protocol for the synthesis of ynones from lithium alkynyltriisopropoxyborates with acid chlorides under mild neutral conditions.

The palladium-catalyzed addition of aryl- and alkenylboronic acids to 4-hydroxy-2-alkynecarboxylates and in situ lactonization would constitute a novel methodology for the synthesis of various butenolides with an excellent stereoselectivity and a high control of regioselectivity.

Lithium alkynyltriisopropoxyborates were homocoupled in the presence of palladium acetate and DPEPhos. This protocol allows a new efficient route to synthesis of 1,3-diynes under very mild conditions.

The palladium-catalyzed cycloreduction of 5-allen-1-ynes gave the corresponding 1,2-bisalkylidenecyclopentanes in excellent chemoselectivity and chemical yields. Incorporating an electron-withdrawing group at the acetylenic position showed to be better substrates for the present cycloreduction.

Since then, transition metal-catalyzed addition tounsaturated bonds with organometallic compounds has beena subject of intensive work in the area of organic andorganometallic chemistry. Use of the chiral BINAP-rhodiumcatalyst was further demonstrated to achieve asymmetricadditions of organoboronic acids to various carbonyl com-pounds.

The N-alkyl-2,3-epoxypropylamines (2) formed from primary alkylamines (1) and epichlorohydrin were chemoselectively rearranged to the four-membered rings, N-alkylazetidin-3-ols (3), upon treatment of triethylamine in refluxing acetonitrile.

The palladium-catalyzed addition reaction of alkenyl- or aryl-boronic acids into various allenes is described, which allows C–C bond formation in a highly regioselective manner under very mild conditions.

Haloene-ynes 1 with a palladium catalyst would form the alkenylpalladium intermediates via intramolecular Heck reactions, which were reductively cleaved with triethylsilane or formate ligand to give the cycloreduction products 3 in good to excellent yields.

2-Bromo-1,6-enynes 5 with a palladium catalyst would form the alkenylpalladium intermediates via an intramolecular Heck reaction, which were cross-coupled with various organoboronic acids 8 to give the cyclization–coupling products 6 in synthetically valuable yields.

Cascade palladium-catalyzed cycloalkylations of 2-bromo-1,n-dienes were accomplished in good to excellent yields, where the alkylpalladium intermediates, formed via an intramolecular Heck reaction of 2-bromo-1,n-dienes (n = 6 or 7), were successfully cross-coupled with various organoboronic acids. The optimal yields were achieved by the use of cesium carbonate in ethanol with Pd(PPh(3))(4) as catalyst, with 2-bromo-1,n-dienes and organoboronic acids at concentrations of 0.2 and 0.3 M (1.5 equiv), respectively.

[reaction: see text] Unusual palladium-catalyzed arylative fragmentations of acyclic 3-allen-1-ols were observed. Oxidative addition of Pd(0) to aryl halides would form the arylpalladium halides, which added to the central carbon of allenes via carbopalladation to form the pi-allylpalladium intermediates. The pi-allylpalladium intermediates would be reductively eliminated via carbon-carbon cleavage to give the arylated dienes and the alpha-hydroxyalkylpalladium intermediates, which were further reductively eliminated to the corresponding aldehydes.

A new Si thin-film transistor (TFT) has been proposed where only one grain boundary exists midway between the source and drain. The proposed device was fabricated by a novel excimer-laser crystallization method, and the device characteristics were evaluated. The article shows schematics of the proposed TFT having the unique feature that there is only one grain boundary in the channel. Since the source and drain are in their own grains with good crystallinity, leakage current of the TFT under off-conditions is expected to be as low as that of MOST in ULSIs. Since a potential barrier formed at the boundary is low for an excimer-laser-annealed poly-Si film and number of grain boundaries is only one, the on-current is expected to be as high as that of MOST. Deep traps at the grain boundary can act effectively as a carrier recombination center, and they can potentially kill the undesirable kink effect.

Overview of U.S. Federal Laws and Regulations Affecting Mixed Waste Treatment, M. Knecht Waste Characterization & Classification Sample Collection Design, J. Maney Analytical Technology, S. Goheen Statistical Inference, E. Chai Other Characterization and Classification, R. Montgomery Separation Techniques In-situ Remediation of Contaminated Soils by Electrokinetic Processes, S. Pamukcu and C. Huang Mercury Separation, T. Klasson Separation of Radionuclides from Aqueous Mixed-Waste Solutions Using Liquid-Liquid Extraction Processes, T. Todd, J. Law, and R. Herbst Thermal Treatment Technologies Incineration, J. McFee, C. Pfrommer, Jr., and M. Aident Vitrification, I. Pegg and I. Joseph Application of Steam-Reforming to Various Types of Radwaste, T. Galloway, M. Cage, and T. Snyder Wet Air Oxidation, R. Shah and R. Mahalingam Supercritical Water Oxidation, P. Savage and C. Oh Thermal Desorption, G. Stegemeier, H. Vinegar, P. Sadler Molten Salt Oxidation, P. Hsu and M. Adamson Fluidized-Bed Calcination, J. Christian Non-thermal Treatment Technologies Supercritical Fluid Extraction for Nuclear Waste Treatment, C. Wai Electrochemical or Direct Chemical Oxidation, B. Balazs, Z. Chiba, M. Adamson, R. Pierce, N. Nelson, J. Cooper, P. Hsu, and P. Lewis Electrohydraulic Cavitation and Sonolysis, M. A. Beckett, J. Schramm, G. Zhang, and I. Hua Gas Phase Destruction, B. Penetrante and L. Rosocha Radiation Induced Oxidation, W. Cooper, M. Nickelsen, T. Tobien, and B. Mincher Phytoremediation, G. Lanza and P. Flathman Stabilization and Solidification Technologies Generals of Mixed Waste Solidification and Stabilization Methods, V. Maio Chemical Fixation and Stabilization, C. Langton Chemically Bonded Phosphate Ceramics for Mixed Waste Stabilization and Solidification, A. Wagh, D. Singh, and S. Jeong Polyester Resin Microencapsulation, R. Biyani , P. Agamuthu, and R. Mahalingam Polyethylene Encapsulation, P. Kalb Sulfur Polymer Encapsulation, P. Kalb In-situ Buried Waste Stabilization Using Jet Grouting, G. Loomis, R. Farnsworth, and J. Jessmore Offgas Control for Mixed Waste Thermal Treatment Systems, N. Soelberg Introduction Design and Performance Objectives for Offgas Control Systems Input Offgas Flowrates and Compositions Examples of Existing Offgas Systems for Mixed Waste Treatment APCS Designs for Complying with New Regulations Mercury Emissions Control Technologies for Mixed Waste Treatment Offgas System Design and Capital Cost Estimates Conclusions and Recommendations Decontamination, J. Tripp, R. Demmer, and R. Meservey Decontamination Techniques Mechanical Surface Removal Methods Chemical Decontamination Biological Decontamination Bulk Decontamination Defining Terms References System Integration and Deployment Integration of Mixed Waste Treatment into an Environmental and Quality Management System, J. Meagher Risk Analysis and Toxicology, R. Vanhorn Planned Life-Cycle Cost Estimates, W. Schwinkendorf