Bifunctional Chiral Electrocatalysts Enable Enantioselective α-Alkylation of Aldehydes.

Herein, we describe an innovative approach to the asymmetric electrochemical α-alkylation of aldehydes facilitated by a newly designed bifunctional chiral electrocatalyst. The highly efficient bifunctional chiral electrocatalyst combines a chiral aminocatalyst with a redox mediator. It plays a dual role as a redox mediator for electrooxidation, while simultaneously providing remarkable asymmetric induction for the stereoselective α-alkylation of aldehydes. Additionally, this novel catalyst exhibits enhanced catalytic activity and excellent stereoselective control comparable to conventional catalytic systems. As a result, this strategy provides a new avenue for versatile asymmetric electrochemistry. The electrooxidation of diverse phenols enables the C-H/C-H oxidative α-alkylation of aldehydes in a highly chemo- and stereoselective fashion. Detailed mechanistic studies by control experiments and cyclic voltammetry analysis demonstrate possible reaction pathways and the origin of enantio-induction.

Green process innovation, green product innovation, leverage, and corporate financial performance; evidence from system GMM.

Natural resource usage has produced various environmental challenges. Green process innovation has been considered a viable option that can help both industry and society. This study investigates the impact of green process innovation and green product innovation on corporate financial performance. We based our findings on a sample of 280 listed non-financial firms operating in South Asia. Information was gathered from firms' annual and CSR reports from 2012 to 2022. This study's data was analyzed using a two-step dynamic panel system GMM, correlation analysis, multicollinearity diagnostic tests, and descriptive statistics. Corporate financial performance is measured with ROA, ROE and Tobin's Q. Overall findings of the study show that green innovation has a significant positive impact on all measures of financial performance. Investing in the innovation of green products and green process can assist businesses in avoiding environmental concerns and regulatory penalties, while also assisting them in establishing new market prospects and achieving new levels of success with their green products. In addition, developing products that are friendly to the environment is tightly connected to expanding green competencies, promoting a company's green image, and improving the company's financial performance. Particularly useful for policymakers in developing countries, the study's findings can be used to introduce paradigm-shifting legislation and penalties that speed up business adoption of green process innovation.

Effects of microcystin on protein profile in hepatopancreas of Litopenaeus vannamei.

For intensive aquaculture in freshwater ponds, microcystin (MC-LR) generated from cyanobacterial blooms is one of the bottlenecks for the healthy and sustainable development of shrimp aquaculture industry. In this study, we measured the MC-LR content in the hepatopancreas and muscles of Litopenaeus vannamei stressed by MC-LR, and analyzed protein expression in the hepatopancreas using DIA high-throughput proteomics technology. The results showed that MC-LR content in the hepatopancreas and muscles reached the highest at 1 h after MC-LR injection, which was (6.12±0.45) µg·kg-1 and (5.00±0.19) µg·kg-1, respectively. Then, it decreased gra-dually, with that in the hepatopancreas being significantly higher than in muscles. We identified 820 differential expressed proteins, including 586 up-regulated and 234 down-regulated ones. Results of bioinformatics analysis showed that MC-LR stress significantly affected immune-related pathways such as lysosome, RIG-Ⅰ receptor signals and interleukin-2. It also altered energy metabolisms including citrate cycle, metabolism of starch and sucrose, and interconversion of pentose and glucoronate, which in turn led to the disorder of carbohydrate metabolism. In addition, MC-LR significantly upregulated 19 cytoskeleton-related blood shadow proteins and damaged the hepatopancreas cytoskeleton. It was concluded that MC-LR mainly affected the physiological processes associated with immunity, energy metabolism, and cytoskeleton in the hepatopancreas of L. vannamei.

Asymmetric organocatalytic direct aldol reactions of ketones with alpha-keto acids and their application to the synthesis of 2-hydroxy-gamma-butyrolactones.

A variety of organocatalysts for the asymmetric direct aldol reactions of ketones with alpha-keto acids were designed on the basis of molecular recognition and prepared from proline and aminopyridines. The organic molecule 8e, derived from proline and 6-methyl-2-amino pyridine, was the best catalyst, affording excellent enantioselectivities (up to 98% ee) for the direct aldol reactions of acetone or 2-butanone with a wide range of alpha-keto acids and for the reactions of various acyclic aliphatic ketones with 3-(2-nitrophenyl)-2-oxopropanoic acid. The aldol adducts could be converted to 2-hydroxy-gamma-butyrolactones by reaction sequences of diastereoselective reduction and lactonization. Experimental and theoretical studies on the transition states revealed that the amide N-H and the pyridine N of the organocatalyst selectively form hydrogen bonds with the keto oxygen and the carboxylic acid hydroxy of the alpha-keto acid, respectively. These two hydrogen-bonding interactions are important for the reactivity and enantioselectivity of the direct asymmetric aldol condensation.

Design of organocatalysts for asymmetric direct syn-aldol reactions.

Two new organocatalysts 3a and 3b, derived from L-leucine and (S)-beta-amino alcohols that were prepared from L-valine, were designed and afforded the direct syn-aldol reactions of a wide scope of aldehydes with various ketones with an excellent diastereomeric ratio of up to >20/1 and enantioselectivities of up to 99% ee.