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Free, publicly-accessible full text available March 7, 2023
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Subsurface drainage has been widely accepted to mitigate the hazard of landslides in areas prone to flooding. Specifically, the use of drainage wells with pumping systems has been recognized as an effective short-term solution to lower the groundwater table. However, this method has not been well considered for long-term purposes due to potentially high labor costs. This study aims to investigate the idea of an autonomous pumping system for subsurface drainage by leveraging conventional geotechnical engineering solutions and a deep learning technique—Long-Short Term Memory (LSTM)—to establish a geotechnical cyber-physical system for rainfall-induced landslide prevention. For this purpose, a typical soilmore »Free, publicly-accessible full text available February 1, 2023
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Free, publicly-accessible full text available February 1, 2023
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Free, publicly-accessible full text available December 7, 2022
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Free, publicly-accessible full text available October 1, 2022
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Free, publicly-accessible full text available November 1, 2022
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Propargyl amines are versatile synthetic intermediates with numerous applications in the pharmaceutical industry. An attractive strategy for efficient preparation of these compounds is nitrene propargylic C(sp3)−H insertion. However, achieving this reaction with good chemo-, regio-, and enantioselective control has proven to be challenging. Here, we report an enzymatic platform for the enantioselective propargylic amination of alkynes using a hydroxylamine derivative as the nitrene precursor. Cytochrome P450 variant PA-G8 catalyzing this transformation was identified after eight rounds of directed evolution. A variety of 1-aryl-2-alkyl alkynes are accepted by PA G8, including those bearing heteroaromatic rings. This biocatalytic process is efficient andmore »Free, publicly-accessible full text available December 23, 2022
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Chiral amines can be made by insertion of a carbene into an N–H bond using two-catalyst systems that combine a transition metal-based carbene-transfer catalyst and a chiral proton-transfer catalyst to enforce stereocontrol. Haem proteins can effect carbene N–H insertion, but asymmetric protonation in an active site replete with proton sources is challenging. Here we describe engineered cytochrome P450 enzymes that catalyse carbene N–H insertion to prepare biologically relevant α-amino lactones with high activity and enantioselectivity (up to 32,100 total turnovers, >99% yield and 98% e.e.). These enzymes serve as dual-function catalysts, inducing carbene transfer and promoting the subsequent proton transfer withmore »Free, publicly-accessible full text available October 18, 2022