Enantioselective Synthesis of Cyclopentenes by (3+2) Annulation via a 2-Carbon Phosphonium.

Herein we report a catalytic enantioselective (3+2) annulation, in which a vinyl phosphonium intermediate serves as the 2-carbon component. The reaction involves an α-umpolung β-umpolung coupling sequence, enabled by β-haloacrylates and chiral enantioenriched phosphepine catalysts. The reaction shows good generality, providing access to an array of cyclopentenes, with mechanistic studies supporting stereospecific formation of the vinyl phosphonium intermediate which, then undergoes annulation with turn over limiting catalyst elimination.

Radical Coupling Initiated by Organophosphine Addition to Ynoates.

Dual nucleophilic phosphine photoredox catalysis is yet to be developed due to facile oxidation of the phosphine organocatalyst to the phosphoranyl radical cation. Herein, we report a reaction design that avoids this event and exploits traditional nucleophilic phosphine organocatalysis with photoredox catalysis to allow the Giese coupling with ynoates. The approach has good generality, while its mechanism is supported by cyclic voltametric, Stern-Volmer quenching, and interception studies.

Multifaceted View on the Mechanism of a Photochemical Deracemization Reaction.

Upon irradiation in the presence of a chiral benzophenone catalyst (5 mol %), a racemic mixture of a given chiral imidazolidine-2,4-dione (hydantoin) can be converted almost quantitatively into the same compound with high enantiomeric excess (80-99% ). The mechanism of this photochemical deracemization reaction was elucidated by a suite of mechanistic experiments. It was corroborated by nuclear magnetic resonance titration that the catalyst binds the two enantiomers by two-point hydrogen bonding.

Photochemical Deracemization at sp-Hybridized Carbon Centers via a Reversible Hydrogen Atom Transfer.

A photochemical deracemization of 5-substituted 3-phenylimidazolidine-2,4-diones (hydantoins) is reported (27 examples, 69%-quant., 80-99% ). The reaction is catalyzed by a chiral diarylketone which displays a two-point hydrogen bonding site.

Bi- and poly(carbyne) functionalised polycyclic aromatics.

Complexes where a central polyaromatic ring system is substituted with one to four tungsten carbynes have been prepared by Pd0/AuI-mediated coupling between a tungsten stannylcarbyne and aryl halides. This strategy enables preparation of complexes with one to three carbynes substituted onto a single phenyl ring, the first anthracenyl mono- and bis-carbynes, and a tetra(carbyne) complex constructed about a central pyrene ring system.

Decision-making dysregulation in first-episode schizophrenia.

Studies with chronic schizophrenia patients have demonstrated that patients fluctuate between rigid and unpredictable responses in decision-making situations, a phenomenon which has been called dysregulation. The aim of this study was to investigate whether schizophrenia patients already display dysregulated behavior at the beginning of their illness. Thirty-two first-episode schizophrenia or schizophreniform patients and 30 healthy controls performed the two-choice prediction task.

The acoustic startle reflex and its modulation: effects of age and gender in humans.

The acoustic startle reflex and its modulation by prepulse inhibition (PPI) and habituation are used in many studies in different fields of neuropsychiatric research. The aim of this study was to examine the effects of age and gender on PPI, startle magnitude, and habituation in healthy human volunteers. Twenty-seven male and 28 female participants of four different age groups (range: 20-60 years) were investigated in an acoustic startle paradigm using a startle stimulus of 115 dB and a prepulse of 86 dB (16 dB over the white noise background) with five different lead intervals (30, 60, 120, 240, and 2000 ms).