Nickel-Catalyzed Sulfonylation of Aryl Bromides Enabled by Potassium Metabisulfite as a Uniquely Effective SO Surrogate.

The development and mechanistic investigation of a nickel-catalyzed sulfonylation of aryl bromides is disclosed. The reaction proceeds in good yields for a variety of substrates and utilizes an inexpensive, stench-free, inorganic sulfur salt (K S O ) as a uniquely effective SO surrogate. The active oxidative addition complex was synthesized, isolated, and fully characterized by a combination of NMR spectroscopy and X-ray crystallography analysis.

Nickel-Catalyzed Cyanation of (Hetero)aryl Bromides Using DABAL-Me as a Soluble Reductant.

A nickel-catalyzed cyanation of (hetero)aryl halides using air-stable bis(trimethylaluminum)-1,4-diazabicyclo[2.2.2]octane (DABAL-Me) as a soluble reductant has been developed.

Air-Tolerant Nickel-Catalyzed Cyanation of (Hetero)aryl Halides Enabled by Polymethylhydrosiloxane, a Green Reductant.

An air-tolerant nickel-catalyzed cyanation of aryl bromides is reported. The reaction uses a NiCl/Xantphos catalyst in combination with substoichiometric quantities of zinc cyanide and polymethylhydrosiloxane. This silane is a green, homogeneous alternative to the traditional, insoluble solid reductant zinc and renders the reaction tolerant to air.

Intermolecular Stereoselective Iridium-Catalyzed Allylic Alkylation: An Evolutionary Account.

Our lab has long been interested in the development of methods for the creation of enantioenriched all-carbon quaternary stereocenters. Historically, our interest has centered on palladium-catalyzed allylic alkylation, though recent efforts have moved to include the study of iridium catalysts. Whereas palladium catalysts enable the preparation of isolated stereocenters, the use of iridium catalysts allows for the direct construction of vicinal stereocenters via an enantio-, diastereo-, and regioselective allylic alkylation.

Intramolecular Hydrogen Shift Chemistry of Hydroperoxy-Substituted Peroxy Radicals.

Gas-phase autoxidation - the sequential regeneration of peroxy radicals (RO) via intramolecular hydrogen shifts (H-shifts) followed by oxygen addition - leads to the formation of organic hydroperoxides. The atmospheric fate of these peroxides remains unclear, including the potential for further H-shift chemistry. Here, we report H-shift rate coefficients for a system of RO with hydroperoxide functionality produced in the OH-initiated oxidation of 2-hydroperoxy-2-methylpentane.

Synergistic O + OH oxidation pathway to extremely low-volatility dimers revealed in β-pinene secondary organic aerosol.

Dimeric compounds contribute significantly to the formation and growth of atmospheric secondary organic aerosol (SOA) derived from monoterpene oxidation. However, the mechanisms of dimer production, in particular the relevance of gas- vs. particle-phase chemistry, remain unclear.

Enantioselective Synthesis of Vicinal All-Carbon Quaternary Centers via Iridium-Catalyzed Allylic Alkylation.

The development of the first enantioselective transition-metal-catalyzed allylic alkylation providing access to acyclic products bearing vicinal all-carbon quaternary centers is disclosed. The iridium-catalyzed allylic alkylation reaction proceeds with excellent yields and selectivities for a range of malononitrile-derived nucleophiles and trisubstituted allylic electrophiles. The utility of these sterically congested products is explored through a series of diverse chemo- and diastereoselective product transformations to afford a number of highly valuable, densely functionalized building blocks, including those containing vicinal all-carbon quaternary stereocenters.

Enantioselective Halolactonization Reactions using BINOL-Derived Bifunctional Catalysts: Methodology, Diversification, and Applications.

A general protocol is described for inducing enantioselective halolactonizations of unsaturated carboxylic acids using novel bifunctional organic catalysts derived from a chiral binaphthalene scaffold. Bromo- and iodolactonization reactions of diversely substituted, unsaturated carboxylic acids proceed with high degrees of enantioselectivity, regioselectivity, and diastereoselectivity. Notably, these BINOL-derived catalysts are the first to induce the bromo- and iodolactonizations of 5-alkyl-4( Z)-olefinic acids via 5- exo mode cyclizations to give lactones in which new carbon-halogen bonds are created at a stereogenic center with high diastereo- and enantioselectivities.

Atmospheric autoxidation is increasingly important in urban and suburban North America.

Gas-phase autoxidation-regenerative peroxy radical formation following intramolecular hydrogen shifts-is known to be important in the combustion of organic materials. The relevance of this chemistry in the oxidation of organics in the atmosphere has received less attention due, in part, to the lack of kinetic data at relevant temperatures. Here, we combine computational and experimental approaches to investigate the rate of autoxidation for organic peroxy radicals (RO) produced in the oxidation of a prototypical atmospheric pollutant, -hexane.

Asymmetric Synthesis of All-Carbon Quaternary Spirocycles via a Catalytic Enantioselective Allylic Alkylation Strategy.

Rapid access to enantioenriched spirocycles possessing a 1,4-dicarbonyl moiety spanning an all-carbon quaternary stereogenic spirocenter was achieved using a masked bromomethyl vinyl ketone reagent. The developed protocol entails an enantioselective palladium-catalyzed allylic alkylation reaction followed by a one-pot unmasking/RCM sequence that provides access to the spirocyclic compounds in good yields and selectivities.

Enantioselective Synthesis of Acyclic α-Quaternary Carboxylic Acid Derivatives through Iridium-Catalyzed Allylic Alkylation.

The first highly enantioselective iridium-catalyzed allylic alkylation that provides access to products bearing an allylic all-carbon quaternary stereogenic center has been developed. The reaction utilizes a masked acyl cyanide (MAC) reagent, which enables the one-pot preparation of α-quaternary carboxylic acids, esters, and amides with a high degree of enantioselectivity. The utility of these products is further explored through a series of diverse product transformations.

Enantioselective Iridium-Catalyzed Allylic Alkylation Reactions of Masked Acyl Cyanide Equivalents.

The first enantioselective iridium-catalyzed allylic alkylation reaction of a masked acyl cyanide (MAC) reagent has been developed. The transformation allows for the use of an umpoled synthon, which serves as a carbon monoxide equivalent. The reaction proceeds with good yield and excellent selectivity up to gram scale for a wide range of substituted allylic electrophiles, delivering products amenable to the synthesis of highly desirable, enantioenriched vinylated α-aryl carbonyl derivatives.

Iridium-Catalyzed Stereoselective Allylic Alkylation Reactions with Crotyl Chloride.

The development of the first enantio-, diastereo-, and regioselective iridium-catalyzed allylic alkylation reaction of prochiral enolates to form an all-carbon quaternary stereogenic center with an aliphatic-substituted allylic electrophile is disclosed. The reaction proceeds with good to excellent selectivity with a range of substituted tetralone-derived nucleophiles furnishing products bearing a newly formed vicinal tertiary and all-carbon quaternary stereodyad. The utility of this protocol is further demonstrated via a number of synthetically diverse product transformations.

Diastereoselective addition of monoorganocuprates to a chiral fumarate: reaction development and synthesis of (-)-dihydroprotolichesterinic acid.

Recent studies of diastereoselective conjugate additions of monoorganocuprates, Li[RCuI], to chiral γ-alkoxycrotonates and fumarates are disclosed. This methodology was applied to the shortest total synthesis of (-)-dihydroprotolichesterinic acid to date, but several attempts to prepare other succinate-derived natural products, such as pilocarpine and antrodin E, were unsuccessful.

Total synthesis of (-)-dihydroprotolichesterenic acid via diastereoselective conjugate addition to chiral fumarates.

A diastereoselective conjugate addition of a variety of monoorganocuprates, Li[RCuI], to chiral fumarates to provide funtionalized succinates has been developed. The utility of this reaction is demonstrated in a concise total synthesis of (-)-dihydroprotolichesterenic acid that required only four steps and proceeded in an overall 31% yield.

Enantioselective iodolactonization of disubstituted olefinic acids using a bifunctional catalyst.

The enantioselective iodolactonizations of a series of diversely substituted olefinic carboxylic acids are promoted by a BINOL-derived, bifunctional catalyst. Reactions involving 5-alkyl- and 5-aryl-4(Z)-pentenoic acids and 6-alkyl- and 6-aryl-5(Z)-hexenoic acids provide the corresponding γ- and δ-lactones having stereogenic C-I bonds in excellent yields and >97:3 er. Significantly, this represents the first organocatalyst that promotes both bromo- and iodolactonization with high enantioselectivities.

Case report: Diagnosis and treatment of a botryoid odontogenic cyst found in the maxillary anterior region.

Introduction: The botryoid odontogenic cyst (BOC) is a multicompartmentalized variant of the lateral periodontal cyst (LPC) that is typically found in the premolar-canine region of the mandible.

Methods: A 60-year old man was referred for evaluation of a radiolucent lesion discovered on a routine examination. Radiographs revealed a unilocular radiolucency between the roots of teeth #10 and #11.

Pharmaceutical care: new management and leadership imperatives.

The management imperatives for pharmaceutical care concern themselves with complexity, while leadership imperatives are concerned with effecting change. Both "species" of action are needed to support the paradigm shift associated with pharmaceutical care. Pharmacy managers must be the architects and engineers of the new dimensions of complexity associated with pharmaceutical care while also serving as zealots of change for pharmaceutical care within their departments and hospitals.