[ORG-39]Structure engineering of porphyrin-based hole transporting materials for perovskite solar cells

Perovskite solar cells (PSCs) are a new type of organic-inorganic thin-film solar cells developed from dye-sensitized solar cells. Due to its high efficiency, low cost and easy preparation characteristics, perovskite solar cells have attracted the research interest of a huge number of scientific researchers and have achieved very significant achievements. From 2009 to the present, its light conversion efficiency has increased from 3.8% [1] Increased to 25.2% [2]. However, hole transport materials like Spiro-OMeTAD which was used mostly in perovskite solar cell often needed doping to increase its mobility, and this would decrease its stability, which was unfavorable for its scalable application.
Herein, four porphyrin-based hole transport materials (HTM) were designed, synthesized, and used in perovskite solar cell. Compared with traditional HTM Spiro-OMeTAD, they were more convenient to synthesize and non-doped. They got a comparable power conversion efficiency of 18.12%, which is just slightly lower than Spiro-based device (19.71%). At the same time, the device of based on these four new HTM could remain at least 80% of their efficiency after 31 days under ambient environment, while Spiro-based device degraded to 54% of its original efficiency.
Fig.

Continue reading

[ORG-38]Discovery of antibacterial inhibitors with benzamide skeleton targeting the bacterial cell division protein FtsZ

With the rise of antibiotics resistance worldwide, it is necessary to develop new antibacterial agents with new mechanisms for killing the emerging antibiotic-resistant bacteria. FtsZ is a new promising target for new antibiotics, which forms a Z-ring and then further regulates bacterial cell division. Here with analysis of the structure-activity relationship of PC190723, this research aims to develop a novel class of benzamide-skeleton compounds which can inhibit FtsZ protein and kill bacteria, and to optimize their pharmacokinetics for the discovery of a drug candidate that can enter clinical trial.

Continue reading

[ORG-37]Ruthenium-catalyzed regioselective allylic C-H amidation

Herein we report a ruthenium catalyzed regioselective allylic C—H amidation. By employing [Ru(cymene)Cl2]2 as catalyst, C—H activation and nitrene insertion are sequentially perform, followed by a reductive elimination, selectively construct a C—N bond on branch position in metal pi-allyl intermediate. Nitrene precursors such as sulfonylazide and dioxazolone are successfully insert to both activated and non-activated olefin. This strategy provides a simple, cheap method for constructing C—N bond on simple olefin, which potentially useful in late stage functionalization.

Continue reading

[ORG-36]DABCO-promoted diaryl thioether formation by metal-catalyzed coupling of sodium sulfinates and aryl iodides

Diaryl thioethers are usually synthesized from thiols in which industrial-scale use is discouraged by the repulsive odor and toxicity. A scalable reaction protocol for diaryl thioether synthesis using sodium arylsulfinates and iodoarenes is presented. Upon the presence of copper or palladium catalysts and DABCO, thioethers can be synthesized in moderate to good yield with broad substrate scope. The mechanistic study showed that radical process was involved, while DABCO-N-oxide radical can be identified by HRMS analysis. A plausible mechanism suggests a synergistic reduction of sulfinate by Cu(II) and DABCO, followed by cross-coupling with aryl iodide to afford the desired product.

Continue reading

[ORG-34]Pd-catalyzed cross-coupling of highly sterically congested enol carbamates with Grignard reagents via C−O bond activation

This poster includes the background of this study and the major results.
The major part of this study focuses on Pd-catalyzed highly sterically hindered cross-coupling reaction between enol carbamates and Grignard reagents, which is presented for the first time. Broad scope of alkenes was synthesized with high stereoselectivity. Furthermore, the successful synthesis of Tamoxifen is achieved by this strategy.

Continue reading

[ORG-33]HNTf2-catalyzed synthesis of hydrodibenzofurans

Described here is a highly efficient synthesis of hydrodibenzofurans, an important structural unit lacking general access, in particular, with contiguous quaternary stereocenters. In the presence of HNTf2 as the superior catalyst and mCPBA as an oxidant, the readily available styrene substrates underwent a one-pot cascade process comprising epoxidation, semipinacol rearrangement, and hemiketal formation to furnish hydrodibenzofurans with good efficiency and diastereoselectivity.

Continue reading

[ORG-32]Organocatalytic enantioselective synthesis of α-amino ketones from sulfonium ylides

Herein we disclose a new catalytic asymmetric approach for the synthesis of chiral α-amino ketones, which is particularly useful for the less accessible acyclic α-tertiary cases. By a protonation-amination sequence, our approach represents a rare asymmetric H−heteroatom bond insertion by α-carbonyl sulfonium ylides, an attractive surrogate of diazocarbonyls. The mild intermolecular C–N bond formation was catalyzed by chiral phosphoric acids with excellent efficiency and enantioselectivity. The products are precursors to other important chiral amine derivatives, including drug molecules and chiral ligands. The enantioselectivity was controlled by dynamic kinetic resolution in the amination step, rather than the initial protonation.

Continue reading

[ORG-31]Highly enantioselective hydrogenation of tri-substituted α,β-unsaturated carboxylic acids with O-SDP

We herein present the design and synthesis of a structurally unique oxa-spirocyclic bisphosphine ligand, termed as O-SDP. The bisphosphine ligand O-SDP derived from O-SPINOL has a relatively larger bite angle compared with that of SDP, and O-SDP has been successfully applied in the ruthenium-catalyzed asymmetric hydrogenation of tetra-substituted and tri-substituted α,β-unsaturated carboxylic acids under base-free conditions.
The synthetic utility of the protocol is highlighted by its synthetic application in key intermediates for chiral drugs.

Continue reading

[ORG-30] Preparation of the anti-cancer drug wogonin by desolvation

Wogonin is a natural flavonoid isolated in a plant known as Scutellaria baicalensis or Skullcap. Studies found wogonin has anti-cancer property but very few reported about its structural chemistry. This study will explore the crystal structure of anhydrous wogonin via desolvation. The ethyl acetate solvate crystals (left) was heated under mild condition which afforded a new stable anhydrous form of wogonin (right), with a triclinic P-1 crystal. PXRD and thermogravimetric analyses validated the results.

Continue reading