Showing papers by "Hiroaki Sasai published in 2023"
1 citations
TL;DR: In this paper , a photoisomerization of photoresponsive units on the catalysts leads to the control of the catalytic activity and/or selectivity of the enantioselective reactions.
Abstract: This study presents recent advances in photoswitchable chiral organocatalysts and their applications in the photomodulation of enantioselective reactions. Under irradiation with an appropriate wavelength of light, the E/Z‐photoisomerization of the photoresponsive units on the catalysts leads to the control of the catalytic activity and/or selectivity of the enantioselective reactions. Additionally, this study elucidates the design, synthesis, and catalytic application of the fabricated azobenzene BINOL‐based photoswitchable chiral phase‐transfer catalysts. This account will provide insights into the appropriate design of a photoswitchable chiral organocatalyst that can achieve both good enantioselectivity and photocontrol.
1 citations
TL;DR: In this paper , a two-pot synthesis of unsymmetrical hetero[7]helicenes from commercially available substrates has been established, combining the acid-mediated annulation with the electrochemical domino reaction (oxidative hetero-coupling/dehydrative cyclization sequence) in a single protocol.
TL;DR: In this paper , a BO-assisted screening was applied to identify improved reaction conditions toward a hundred-gram scale-up synthesis of 2,3,7,8-tetrathiaspiro[4.4]nonane.
Abstract: Bayesian optimization (BO)-assisted screening was applied to identify improved reaction conditions toward a hundred-gram scale-up synthesis of 2,3,7,8-tetrathiaspiro[4.4]nonane (1), a key synthetic intermediate of 2,2-bis(mercaptomethyl)propane-1,3-dithiol [tetramercaptan pentaerythritol]. Starting from the initial training set (ITS) consisting of six trials sampled by random screening for BO, suitable parameters were predicted (78% conversion yield of spiro-dithiolane 1) within seven experiments. Moreover, BO-assisted screening with the ITS selected by Latin hypercube sampling (LHS) further improved the yield of 1 to 89% within the eight trials. The established conditions were confirmed to be satisfactory for a hundred grams scale-up synthesis of 1.
TL;DR: In this paper , a facile and green approach for the Markovnikov-selective hydroamination of styrene with naphthylamine through irradiation with UV LED light (365 nm) via an electron donor-acceptor complexation was presented.
Abstract: This study processes a facile and green approach for the Markovnikov-selective hydroamination of styrene with naphthylamine through irradiation with UV LED light (365 nm) via an electron donor–acceptor complexation between naphthylamines and oxygen in situ. This protocol showcases the synthetic potential for aerobic C–N bond formation without using a metal catalyst and photosensitizer. Three naphthylamines were examined and afforded desired C–N bond formation product in moderate yield.