Highly efficient asymmetric synthesis of α,ß-epoxy esters via one-pot organocatalytic epoxidation and oxidative esterification.

Highly enantioselective synthesis of α,ß-epoxy esters was achieved via one-pot organocatalytic epoxidation and consequent oxidative esterification. Excellent enantioselectivities (up to 99% ee) and good yields were obtained for a variety of α,ß-epoxy esters. The method was readily scaled. Furthermore the product was applied towards the synthesis of (-)-clausenamide with excellent enantioselectivities (>99% ee).

Two-Step Growth of 2D Organic-Inorganic Perovskite Microplates and Arrays for Functional Optoelectronics.

Two-dimensional (2D) perovskites have recently attracted intensive interest for their great stability against moisture, oxygen, and illumination compared with their three-dimensional (3D) counterparts. However, their incompatibility with a typical lithography process makes it difficult to fabricate integrated device arrays and extract basic optical and electronic parameters from individual devices. Here, we develop a combination of solution synthesis and a gas-solid-phase intercalation strategy to achieve hexagonal-shaped 2D perovskite microplates and arrays for functional optoelectronics. The 2D perovskite microplates were achieved by first synthesizing the lead iodide (PbI2) microplates from an aqueous solution and then following with intercalation via the vapor transport method. This method further allows us to synthesize arrays of 2D perovskite microplates and create individual 2D perovskite microplate-based photodetectors. In particular, chlorine (Cl) can be efficiently incorporated into the microplates, resulting in significantly improved performance of the 2D perovskite microplate-based photodetectors.

Asymmetric synthesis and biological activities of natural product (+)-balasubramide and its derivatives.

The natural product (+)-balasubramide (3j) and its derivatives (3a-3i) were synthesized using a two-step asymmetric synthesis, and the biological activities of 3a-3j were determined in vitro. Methyl (2S,3R)-(+)-3-phenyloxirane-2-carboxylate (1h), the asymmetric synthesis of which was described in a previous paper, was selected as the starting material. Compounds 3a-3j were evaluated for their neuroprotective, antioxidative, and anti-neuroinflammatory effects. (+)-Balasubramide and its derivatives with different electronegative groups in the 6-phenyl ring produced little neuroprotection and antioxidation, but induced potent anti-neuroinflammatory effects in BV-2 microglial cells (with the exception of 3g). Compound 3c, with a trifluoromethyl group in its 6-phenyl ring, was a particularly potent anti-neuroinflammatory agent. These results demonstrated that the electronegativity of the 6-phenyl ring of (+)-balasubramide is an important determinant of its inhibitory effect on neuroinflammation. More electronegative substituents result in more potent anti-neuroinflammatory effects. Moreover, cytotoxicity assays indicated no significant effects of the tested compounds.

An organocatalytic cascade reaction of 2-nitrocyclohexanone and α,ß-unsaturated aldehydes with unusual regioselectivity.

An organocatalytic cascade reaction of 2-nitrocyclohexanone and α,ß-unsaturated aldehydes was developed. Bicyclo[3.3.1]nonanone products were obtained with good yields and excellent enantioselectivities. The reaction occurred with unusual regioselectivity. A dienolate-iminium activation mechanism was proposed. The products were transformed to eight-membered cyclic ketones with high enantioselectivity.

Highly enantioselective synthesis of nitrocyclopropanes via organocatalytic conjugate addition of bromomalonate to alpha,beta-unsaturated nitroalkenes.

Highly enantioselective synthesis of nitrocyclopropanes was achieved via the organocatalytic conjugate addition of dimethyl bromomalonate to nitroalkenes and the consequent intramolecular cyclopropanation. 6'-Demethyl quinine was found to be the efficient catalyst. Excellent enantioselectivities, diastereoselectivities, and good yields were obtained for a variety of aryl or heteroaryl nitroethylenes.