Construction of α‑Acyloxy Ketones via Photoredox-Catalyzed O–H Insertion of Sulfoxonium Ylides with Carboxylic Acids

Herein, a photoredox-catalyzed insertion of sulfoxonium ylides with carboxylic acids was advanced under mild and simple conditions, offering a practical approach for preparing α-acyloxy ketones with a broad scope of carboxylic acids. A combined experimental and computational study suggests that this reaction proceeds via a stepwise proton-assisted electron transfer mechanism

Visible-Light Photocatalyzed C3–H Alkylation of 2<i>H</i>‑Indazoles/Indoles with Sulfoxonium Ylides via Diversified Mechanistic Pathways

Herein, the C3–H alkylation of 2H-indazoles and indoles with sulfoxonium ylides is developed under visible-light photocatalysis. This protocol employs easily accessible reagents, and a wide range of 2H-indazoles, indoles, and sulfoxonium ylides are suitable for this reaction to afford the desired products under benign conditions. Synergistic experimental and computational studies suggest that the sulfoxonium ylides involving C3–H alkylation of 2H-indazoles and indoles under visible-light photocatalysis could proceed via different mechanistic pathways. For the C3-alkylation of 2H-indazoles, a triplet energy transfer mechanistic pathway of 2H-indazoles is proposed for quenching the excited photocatalyst. Subsequently, the formed excited triplet state of 2H-indazoles could undergo radical attack on the CS moiety of sulfoxonium ylides. After the dissociation of DMSO and 1,2-H migration, the final product of C3-alkylation of 2H-indazoles could be yielded. However, such a mechanistic pathway is not applicable for indoles. Instead, sulfoxonium ylides could be converted to a C-centered radical in the presence of KH2PO4 under visible-light photoredox conditions. The formed C-centered radical can attack the C3-site of indoles and thus lead to the C3-alkylation product of indoles

Effects of miR-20b on the BMP signaling pathway, as assessed by by western blotting.

<p>a): in the miR-20b overexpression group; b): in miR-20b silenced group. (n = 3, *: P<0.05, **: P<0.01, ***: P<0.001)</p

The relative expression of miR-20b in ventricular septal defect.

<p>VSD: ventricular septal defect group; control: healthy group.</p

Effects of miR-20b on mitochondrial membrane potential (MMP) in differentiated cells.

<p>A: control for miR-20b overexpression; B: miR-20b overexpression; C: control for miR-20b silencing; D: miR-20b silencing. (*: P<0.05)</p

The morphological changes during P19 differentiation (×10) b) The expression of the cTnT protein during differentiation (a).

<p>To investigate the differentiation of P19 cells into mature cardiomyocytes, we used western blotting to identify the expression of the cTnT protein during differentiation. The expression of β-actin was used as a internal control.</p

Luciferase activity assessed by the Dual Luciferase Reporter Assay System.

<p><b>a) Bambi confirmed as the direct target gene of miR-20b.</b> 20b+Bambi: the luciferase activity of Bambi in the miR-20b overexpression group; NC+Bambi: the luciferase activity of Bambi in the control; 20b+mut: the luciferase activity of mutated Bambi in the miR-20b overexpression group. <b>b) miR-20b silencing confirmed. c) miR-20b silencing constant during the differentiation (day 10)</b> (n = 6, ***: P<0.001)</p

Effects of miR-20b on the mitochondrial DNA (mtDNA) copy number.

<p>On the 10th day of differentiation, cellular mtDNA content was assessed by qRT-PCR analysis with primers designed to target the <i>CYTB</i> and 28 S rRNA genes (n = 6). miR-20b-over: miR-20b overexpression cells; miR-20b-in: miR-20b silenced cells. P > 0.05 in comparison with negative control (NC) cells.</p

Effects of miR-20b on cell apoptosis.

<p>a) Apoptosis assayed by binding to Annexin V-APC/7-AAD. b) Apoptosis detected by measurement of Caspase-3 activity. miR-20b-over: miR-20b overexpression cells; miR-20b-in: miR-20b silenced cells. (n = 4, *: P<0.05, **: P<0.01)</p

Sequences of primer used in SYBR Green qPCR.

<p>Sequences of primer used in SYBR Green qPCR.</p