Terpolymerization strategy to achieve high-efficiency organic solar cells via construction of D1-A-D1-D2-type polymer donors.

Novel terpolymers were developed with ester group incorporation (BDT-2EST). DM1 with 5% BDT-2EST possesses suitable crystallinity and miscibility matching with Y6 acceptor to offer an excellent power conversation efficiency up to 17.21%. Moreover, the intertwined random features in DM1 offer robust photovoltaic performances with a broad molecular weight tolerance.

Selective halocyclization and iodosulfonylation of N-benzothiazol-2-yl alkynamides under mild conditions.

The selective halocyclization and iodosulfonylation of N-benzothiazol-2-yl alkynamides under mild conditions is described. An effective synthetic strategy to pyrimidobenzothiazoles via a 6-endo-dig halocyclization of N-benzothiazol-2-yl alkynamides was developed at room temperature with a broad substrate scope. Furthermore, several multisubstituted α,ß-enones were synthesized using the same starting materials.

A Robust Au-C≡C Functionalized Surface: Toward Real-Time Mapping and Accurate Quantification of Fe2+ in the Brains of Live AD Mouse Models.

Described here is that Au-C≡C bonds showed the highest stability under biological conditions, with abundant thiols, and the best electrochemical performance compared to Au-S and Au-Se bonds. The new finding was also confirmed by theorical calculations. Based on this finding, a specific molecule for recognition of Fe2+ was designed and synthesized, and used to create a selective and accurate electrochemical sensor for the quantification of Fe2+ . The present ratiometric strategy demonstrates high spatial resolution for real-time tracking of Fe2+ in a dynamic range of 0.2-120 µM. Finally, a microelectrode array with good biocompatibility was applied in imaging and biosensing of Fe2+ in the different regions of live mouse brains. Using this tool, it was discovered that the uptake of extracellular Fe2+ into the cortex and striatum was largely mediated by cyclic adenosine monophosphate (cAMP) through the CREB-related pathway in the brain of a mouse with Alzheimer's disease.

Highly Stereoselective Gold-Catalyzed Coupling of Diazo Reagents and Fluorinated Enol Silyl Ethers to Tetrasubstituted Alkenes.

We report a highly stereoselective synthesis of all-carbon or fluorinated tetrasubstituted alkenes from diazo reagents and fluorinated enol silyl ethers, using C-F bond as a synthetic handle. Cationic AuI catalysis plays a key role in this reaction. Remarkable fluorine effects on the reactivity and selectivity was also observed.

A general and efficient Lewis acid catalysed Mukaiyama-aldol reaction of difluoroenoxysilanes and ketones.

We report a general and highly efficient Mukaiyama-aldol reaction of ketones and difluoroenoxysilanes. While the reaction of aryl ketones worked efficiently in the presence of Bi(OTf)3, that of aliphatic ketones required the use of Sc(OTf)3. In addition, Sc(OTf)3 was capable of achieving excellent 1,2-selectivity in the corresponding reaction of α,ß-unsaturated ketones. This method provides a facile access to differently substituted ß-hydroxy α,α-difluoro ketones, versatile synthons for difluomethylated tertiary alcohols.

An efficient catalyst-free Mukaiyama-aldol reaction of fluorinated enol silyl ethers with tryptanthrin.

We report an efficient Mukaiyama-aldol reaction of tryptanthrin with fluorinated enol silyl ethers, which is carried out in methanol without the use of any catalyst. This method is applied to the total synthesis of the difluoro analogues of the natural product Phaitanthrin B.

Michael Addition Catalyzed by Chiral Secondary Amine Phosphoramide Using Fluorinated Silyl Enol Ethers: Formation of Quaternary Carbon Stereocenters.

A chiral secondary amine phosphoramide was developed and identified as a powerful catalyst for the Mukaiyama-Michael addition of fluorinated enol silyl ethers to tetrasubstituted olefins. The resulting products are obtained with high enantioselectivities and contain a quaternary carbon stereocenter bearing either a difluoroalkyl or monofluoroalkyl group.

Asymmetric triple relay catalysis: enantioselective synthesis of spirocyclic indolines through a one-pot process featuring an asymmetric 6π electrocyclization.

A rare example of a one-pot process that involves asymmetric triple relay catalysis is reported. The key step is an asymmetric [1,5] electrocyclic reaction of functionalized ketimines. The substrates for this process were obtained in situ in a two-step process that involved the hydrogenation of nitroarenes with a Pd/C catalyst to yield aryl amines and their subsequent coupling with isatin derivatives in a Brønsted acid catalyzed ketimine formation reaction. The electrocyclization was catalyzed by a bifunctional chiral Brønsted base/hydrogen bond donor catalyst. The one-pot process gave the desired products in good yields and with excellent enantioselectivity.

New simple synthesis of ring-fused 4-alkyl-4H-3,1-benzothiazine-2-thiones: Direct formation from carbon disulfide and (E)-3-(2-aminoaryl)acrylates or (E)-3-(2-aminoaryl)acrylonitriles.

A new simple and efficient method to construct ring-fused 4-alkyl-4H-3,1-benzothiazine-2-thione derivatives has been developed from carbon disulfide and (E)-3-(2-aminoaryl)acrylates or (E)-3-(2-aminoaryl)acrylonitriles under mild conditions, without the need for a metal catalyst. The newly developed method tolerates a wide range of substrates in moderate to excellent yields. Moreover, this method is advantageous over previous ones for the easy synthesis of reactants.