Asymmetric Total Synthesis of (-)-Psychotriadine Featuring [3,3]-Rearrangement and Stereo-Controllable Ring-Contraction.

The first asymmetric total syntheses of (-)-psychotriadine () and its putative congener tetrahydropsychotriadine () were accomplished in 12 and 13 steps, respectively, featuring Meerwein-Eschenmoser-Claisen rearrangement and Fischer indolization/Plancher rearrangement cascade. A stereochemically controllable dearomative ring contraction was utilized to create the vicinal quaternary stereocenters. The absolute configuration was confirmed through X-ray crystallography and >200 mg of (90% enantiomeric excess (ee)) was obtained.

The double-edged sword of internet use in China's aging population: thresholds, mediation and digital health policy.

Background: Amid global aging and digital transformation, the dual effects of Internet use on health-its potential benefits and risks-remain a subject of debate. This study investigates the threshold effects of Internet use, the mediating role of physical activity, and the implications for digital health policy in China, revealing a compensation-vulnerability paradox among disadvantaged groups.

Methods: The data were drawn from the 2020 China Family Panel Studies (CFPS), a nationally representative sample comprising 7,308 adults aged ≥45.

Enantioselective Total Syntheses of (-)-Caulamidine D and (-)-Isocaulamidine D and Their Absolute Configuration Reassignment.

The first enantioselective total syntheses of (-)-caulamidine D () and (-)-isocaulamidine D () were accomplished. Their absolute configurations were unambiguously elucidated through X-ray crystallography. The isolated natural samples of both and are determined to be the TFA salts instead of the neutral forms.

Total Synthesis and Structural Reassignment of Aranorosinol A, Aranorosinol B, and EI-2128-1.

Herein, we report a concise and collective total synthesis of three natural products aranorosinol A, aranorosinol B, and EI-2128-1 and also the known penicimutanolone. A unified strategy was conceived, which divergently accessed all four congeners within 9-11 steps (LLS) from a common intermediate. Bisoxirane-directed 1,2-addition was utilized as a key step to generate the desired configuration of the C stereocenter of aranorosinol A and B, 28 years after their first isolation, and these were both assigned as configurations, while the C and C configurations of EI-2128-1 were both determined to be ,-configurations.

Total synthesis of (-)-penicimutanin a and related congeners.

The first total synthesis of penicimutanin A () was achieved within 10 steps (LLS). Key innovations in this synthesis consist of (1) a highly efficient electro-oxidative dearomatization; (2) an unprecedented bisoxirane-directed intermolecular aldol reaction from the sterically hindered face of the ketone and (3) the diastereoselective one-step Meerwein-Eschenmoser-Claisen rearrangement enabling the construction of vicinal quaternary stereocenters. Related family members penicimutanolone () and penicimutatin () have also been synthesized alongside, elucidating their absolute configurations, hence the absolute configuration of .