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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(30):8931-8934
The addition of terminal alkynes to racemic β‐stereogenic α‐keto esters was achieved in high levels of stereoselectivity, affording versatile tertiary propargylic alcohols containing two stereocenters. This environmentally benign enantioconvergent reaction proceeds with perfect atom economy, requires no solvent, and is catalyzed by a non‐toxic zinc salt. The alkyne moiety can be leveraged in downstream transformations including hydrogenation to the corresponding saturated tertiary alcohol, which represents the product of a formal enantioconvergent aliphatic nucleophile addition. 相似文献
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Xiaofu Sun Chunjun Chen Shoujie Liu Song Hong Qinggong Zhu Qingli Qian Buxing Han Jing Zhang Lirong Zheng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(14):4717-4721
Electrochemical reduction of CO2 into energy‐dense chemical feedstock and fuels provides an attractive pathway to sustainable energy storage and artificial carbon cycle. Herein, we report the first work to use atomic Ir electrocatalyst for CO2 reduction. By using α‐Co(OH)2 as the support, the faradaic efficiency of CO could reach 97.6 % with a turnover frequency (TOF) of 38290 h?1 in aqueous electrolyte, which is the highest TOF up to date. The electrochemical active area is 23.4‐times higher than Ir nanoparticles (2 nm), which is highly conductive and favors electron transfer from CO2 to its radical anion (CO2.?). Moreover, the more efficient stabilization of CO2.? intermediate and easy charge transfer makes the atomic Ir electrocatalyst facilitate CO production. Hence, α‐Co(OH)2‐supported atomic Ir electrocatalysts show enhanced CO2 activity and stability. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(10):2697-2701
Noble metals are valued, critical elements whose chemical activation or recycling is challenging, and traditionally requires high temperatures, strong acids or bases, or aggressive complexation agents. By using elementary palladium and gold, demonstrated here is the use of mechanochemistry for noble‐metal activation and recycling by mild, clean, solvent‐free, and room‐temperature chemistry. The process leads to direct, efficient, one‐pot conversion of the metals, including spent catalysts, into either simple water‐soluble salts or metal–organic catalysts. 相似文献
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