Stereoselective Vinylogous Aza-Pummerer Reaction of β,β-Disubstituted Enesulfinamides.

Treatment of multisubstituted NH-enesulfinamides with tosyl isocyanate (TsNCO) at room temperature results in the formation of α-tosylcarbamoyloxy -sulfenyl ketimines with high enantioselectivity. This process is believed to proceed via a vinylogous aza-Pummerer-type reaction pathway in which the sulfinyl oxygen atom in the enesulfinamides undergoes nucleophilic attack on tosyl isocyanate, triggering the subsequent transformations that enable the transfer of chirality from sulfur to carbon.

Stereoselective Cyclopropanation of Multisubstituted Enesulfinamides: Asymmetric Construction of α-Tertiary Cyclopropylamine Derivatives Containing β-Quaternary Stereocenters.

Enesulfinamides with α,β,β-trisubstitution undergo a Simmons-Smith reaction to yield multisubstituted cyclopropylamine derivatives with high stereocontrol. The resulting α-tertiary cyclopropylamine derivatives, which feature β-quaternary stereocenters bearing two electronically and sterically similar substituents (., methyl and ethyl), are seldom achieved by using conventional methods.

Electro-Fenton and Induced Electro-Fenton as Versatile Wastewater Treatment Processes for Decontamination and Nutrient Removal without Byproduct Formation.

It is a long-pursued goal to develop electrified water treatment technology that can remove contaminants without byproduct formation. This study unveiled the overlooked multifunctionality of electro-Fenton (EF) and induced EF (I-EF) processes to remove organics, pathogens, and phosphate in one step without halogenated byproduct formation. The EF and I-EF processes used a sacrificial anode or an induced electrode to generate Fe to activate HO produced from a gas diffusion cathode fed by naturally diffused air.

Stereoselective Construction of Acyclic β,β-Disubstituted Enesulfinamides via Conjugate Addition of Organocuprates to α-Substituted α,β-Unsaturated -Sulfinyl Ketimines.

In the presence of boron trifluoride, conjugate addition of organocuprates to α-substituted α,β-unsaturated --butanesulfinyl ketimines provides facile access to acyclic β,β-disubstituted enesulfinamides with high ratios of geometric isomers. Diverse and challenging to synthesize, multisubstituted aza-enolates bearing two electronically and sterically similar β-substituents, which are important precursors for asymmetric construction of the less accessible acyclic quaternary or tetrasubstituted stereocenters at the α-position of ketimines, can be efficiently prepared in good yields with high stereocontrol.

Robust Performance of SARS-CoV-2 Whole-Genome Sequencing from Wastewater with a Nonselective Virus Concentration Method.

The sequencing of human virus genomes from wastewater samples is an efficient method for tracking viral transmission and evolution at the community level. However, this requires the recovery of viral nucleic acids of high quality. We developed a reusable tangential-flow filtration system to concentrate and purify viruses from wastewater for genome sequencing.

Stereocontrolled α-Allylation of α-Branched --Butanesulfinyl Ketimines via a Michael-Wittig Cascade for the Construction of Acyclic Quaternary Stereocenters.

A single-flask cascade of Michael addition and Wittig olefination was developed to allow the stereoselective α-allylic alkylation of α-branched --butanesulfinyl ketimines for the construction of acyclic quaternary stereocenters bearing two sterically and electronically similar substituents. In this process, BuOK-promoted stereoselective α-deprotonation gives fully substituted aza-enolates with a stereodefined geometry, Michael addition with α,β-unsaturated phosphonates generates C-C bonds with exceptional stereocontrol, and finally paraformaldehyde trapping of the conjugate addition intermediate generates functionalized α-allylated imines.

Prediction models for depression risk among older adults: systematic review and critical appraisal.

Objective: To provide an overview of prediction models for the risk of major depressive disorder (MDD) among older adults.

Methods: We conducted a systematic review combined with a meta-analysis and critical appraisal of published studies on existing geriatric depression risk models.

Results: The systematic search screened 23,378 titles and abstracts; 14 studies including 20 prediction models were included.

Construction of Acyclic Quaternary Stereocenters via Mannich-Type Addition of α,α-Disubstituted --Butanesulfinyl Ketimines to Isatin-Derived Ketimines.

A Mannich reaction of deprotonated, highly enantioenriched α,α-disubstituted --butanesulfinyl ketimines with isatin-derived ketimines was developed to prepare 3-amino-3-substituted oxindoles bearing an acyclic quaternary stereogenic carbon substituted with two sterically similar groups. The excellent stereocontrol of the deprotonation enabled the formation of metalloenamine intermediates with stereodefined geometry, while the precise facial selectivity of the C-C bond formation allowed the construction of contiguous quaternary and tetrasubstituted stereocenters with excellent stereoselectivity.