查看更多>>摘要：The first asymmetric hydrogenation of acyclic tetrasubstituted α,β-unsaturated amides has been achieved by using Rh/DuanPhos complex as a catalyst,delivering chiral β-amino amides with two contiguous chiral centers in excellent yields and high enantioselectivi-ties(up to 99％yield,96％ee),which provides efficient and concise access to valuable β-amino amide derivatives.The gram-scale re-action and efficient transformation of β-amino amide to β-amino acid and β-amino cyanide demonstrated the utility of this method-ology.
查看更多>>摘要：Facile mass transport channel and accessible active sites are crucial for binder-free air electrode catalysts in rechargeable flexible zinc-air battery(ZAB).Herein,a ZnS/NH3 dual-assisted pyrolysis strategy is proposed to prepare N/S-doped hierarchical porous bam-boo carbon cloth(HP-NS-BCC)as binder-free air electrode catalyst for ZAB.BCC fabric with abundant micropores is firstly used as flexible carbon support to facilitate the heteroatom-doping and construct the hierarchical porous structure.ZnS nanospheres and NH3 activization together facilitate the electronic modulation of carbon matrix by N/S-doping and optimize the macro/meso/micropores structure of carbon fibers.Benefiting from the highly-exposed N/S-induced sites with enhanced intrinsic activity,the optimized mass transport of biocarbon fibers,as well as the ultra-large specific surface area of 2436.1 m2·g-1,the resultant HP-NS-BCC catalyst exhib-its improved kinetics for oxygen reduction/evolution reaction.When applied to rechargeable aqueous ZABs,it achieves a significant peak power density of 249.1 mW·cm-2.As binder-free air electrode catalyst,the flexible ZAB also displays stable cycling over 500 cy-cles with a minimal voltage gap of 0.42 V,showcasing promising applications in flexible electronic devices.
查看更多>>摘要：Nitrenes,as neutral monovalent nitrogen-centered molecular species,can insert into various bond or remove nitrogen atoms from amines.Nitrene assisted single-atom skeletal editing,discovered decades ago,provides an efficient approach for the precise alteration of cyclic skeletons.In this review,we briefly summarize early studies on skeletal editing of cyclic frameworks involving nitrene species,and introduce several recent important advances systematically.
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