,'-Di-benzyl-ethyl-enedi-ammonium dichloride.

The isolation and crystalline structure of ,'-di-benzyl-ethyl-enedi-ammonium dichloride, CHN ·2Cl, is reported. This was obtained as an unintended product of an attempted Curtius rearrangement that involved benzyl-amine as one of the reagents and 1,2-di-chloro-ethane as the solvent. Part of a series of reactions of a course-based undergraduate research experience (CURE), this was not the intended reaction outcome.

(1S*,2R*,3S*,4R*,5R*)-5-Tetra-decyloxy-methyl-7-oxabicyclo-[2.2.1]heptane-2,3-dicarb-oxy-lic anhydride.

In the title compound, C23H38O5, the oxabicyclo-[2.2.1]heptane-2,3-dicarb-oxy-lic anhydride unit has a normal geometry and the tetra-decoxymethyl side chain is fully extended.

Relative Stabilities of Transition States Determine Diastereocontrol in Sulfur Ylide Additions onto Chiral N-Sulfinyl Imines.

Additions of methylphenylsulfonium methylide onto chiral non-racemic N-sulfinyl imines (R'-SO-N=CH-R, R'=t-butyl, R=protected diol), followed by ring closure, yield terminal aziridines with high diastereoselectivity. Control reactions have established that both N- and C- iminyl substituents impact product preference, and when properly matched, one addition product is selected almost exclusively. Using solution-phase density functional computational methods, minima and transition state searches have been performed to reveal the structural origins of the diastereoselectivity.

2,6-Dichloro-1-[(1E)-2-(phenyl-sulfon-yl)ethen-yl]benzene.

In the title compound, C(14)H(10)Cl(2)O(2)S, the product of a base-catalyzed condensation followed by deca-rboxylation of the carboxyl-ate group of the sulfonyl derivative, the configuration of the alkene unit is E. The torsion angle between the alkene unit and the 2,6-dichloro-phenyl ring system is -40.8 (3)°.

S-Methylidene Agents: Preparation of Chiral Non-Racemic Heterocycles.

Reaction of sulfur ylide with aldehyde, imine, and ketone functionality affords the desired three-membered heterocycle in excellent yield. The sulfur ylide is generated in situ upon decarboxylation of carboxymethylsulfonium betaine functionality. Of the seven carboxymethylsulfonium betaine derivatives surveyed, the highest level of conversion of π-acceptor to heterocycle was obtained having S-methyl and S-phenyl functionality bound to a thioacetate derivative.

(2S)-2-[(2S*,5R*,6R*)-5,6-Dimeth-oxy-5,6-dimethyl-1,4-dioxan-2-yl]-1-[(S)-1,1-dimethyl-ethylsulfon-yl]aziridine.

The reaction of a sulfur ylide with a chiral non-racemic sulfinyl imine afforded the desired aziridine in excellent yield and subsequent oxidation of the sulfinyl moiety dissolved in anhydrous dichloro-methane using a 75% aqueous solution of 3-chloro-per-oxy-benzoic acid afforded the title compound, C(14)H(27)NO(6)S. The configuration of the newly formed stereogenic center at the point of attachment of the 1,4-dioxane ring to the aziridine ring is S. The configurations of the pre-existing sites 2-, 5-, and 6-positions of the 1,4-dioxane ring prior to reaction of sulfinyl imine with the sulfur ylide are S, R, and R, respectively.

Sulfenylation Chemistry using Polymer-Supported Sulfides.

Clean sulfenylations are observed upon reaction of activated methylenes with phenyl succinimidyl sulfide. When working with diethyl benzylmalonate, the sulfenylated product can be selectively oxidized and thermally fragmented affording phenylsulfenic acid, initially, and diethyl benzylidenemalonate. The developed method was applied using a polymer-supported thioanisole derivative (JandaJel).

Highly stereoselective methylene transfers onto butanediacetal-protected chiral non-racemic sulfinyl imines using S-ylide technology.

Diastereomeric ratios of >95 : 5 were obtained when performing methylene transfers onto imines originating from d-mannitol and (S)-(-)-2-methyl-2-propane sulfinamide or ascorbic acid and (R)-(-)-2-methyl-2-propane sulfinamide.

Synthesis of Chiral Aziridines through Decarboxylative Generation of Sulfur Ylides and their Reaction with Chiral Sulfinyl Imines.

Reaction of sulfur ylide with a series of aryl substituted chiral non-racemic sulfinyl imines afforded the corresponding aziridines in high yield and good stereoselection. The sulfur ylides were generated by the thermally induced decarboxylation of carboxymethylsulfonium betaines. A drop in the diastereomeric ratio was observed when going from electron deficient to electron releasing aryl substituted imines.

Forging Faculty Student Relationships at the College Level Using a Freshman Research Experience.

Coupling the scholarly activities of the chemistry research faculty with that of the freshman Honors general chemistry class has resulted in a rise of productivity within the Department. For seven years, freshman Honors students enrolled in the Honors general chemistry laboratory sections have been assigned to work in the labs of the research active faculty within the Department of Chemistry. Approximately a quarter of those enrolled in the Honors general chemistry laboratory sections elect to continue their research experience.

Aryl-substituted sulfonium betaines: preparation and use in the epoxidation of aldehydes.

Thermally induced decarboxylation of carboxymethylsulfonium betaines results in formation of the corresponding sulfur ylides in situ. Decarboxylation rates for a range of arylcarboxymethylsulfonium betaine salts have been determined using NMR spectroscopy, and the efficiency of ylide generation and trapping has been evaluated via methylidene transfer to a range of aldehydes to form epoxides.

Sulfur ylides via decarboxylation of carboxymethylsulfonium betaines: a novel and mild protocol for the preparation of oxiranes.

A novel protocol for the generation of sulfur ylides is described. The overall process involves thermal decarboxylation of a carboxymethylsulfonium betaine to give a sulfur ylide that, in the presence of an aldehyde, affords the corresponding terminal oxirane. Yields were found to correlate with the electron deficiency of the aryl aldehyde.

Novel Brønsted acidic ionic liquids and their use as dual solvent-catalysts.

The reaction of triphenylphosphine or N-butylimidazole with cyclic sultones gives zwitterions that are subsequently converted into ionic liquids by reaction with trifluoromethane sulfonic acid or p-toluenesulfonic acid. The resulting ionic liquids have cations to which are tethered alkane sulfonic acid groups. These Brønsted acidic ionic liquids are useful solvent/catalysts for several organic reactions, including Fischer esterification, alcohol dehydrodimerization and the pinacol rearrangement.

Stereocontrol in Intermolecular Dirhodium(II)-Catalyzed Carbonyl Ylide Formation and Reactions. Dioxolanes and Dihydrofurans.

Ethyl diazoacetate undergoes dirhodium(II)-catalyzed reactions with aryl aldehydes to form 1,3-dioxolanes as mixtures of diastereoisomers in good yields. Carbonyl ylides are reaction intermediates. Catalyst dependent diastereocontrol is observed for reactions with p-nitrobenzaldehyde, but not for those with p-anisaldehyde or benzaldehyde, so that at least with transformations involving p-nitrobenzaldehyde a metal-stabilized ylide is responsible for product formation.