Organoselenium compounds,due to their high structural diversity,special function,and biological activities,have drawn attention in synthetic chemistry.Herein,a novel example of chiral N,N′-dioxide/cobalt(Ⅱ)complex c...Organoselenium compounds,due to their high structural diversity,special function,and biological activities,have drawn attention in synthetic chemistry.Herein,a novel example of chiral N,N′-dioxide/cobalt(Ⅱ)complex catalyzed asymmetric[2,3]-sigmatropic rearrangement of allylic selenides withα-diazo pyrazoleamides is disclosed,which represents a highly efficient approach to optically active selenides bearing a quaternary C–Se stereocenter.Most of the reactions proceed with 0.5–2 mol%catalyst loading in an inert-free gas atmosphere,and a wealth of chiral selenides are obtained in up to 99% yield and 97%enantiomeric excess(ee).The control experiments demonstrate the high reactivity of allylic selenides,as well as the conspicuous superiority of chiral N,N′-dioxide ligand andα-diazo pyrazoleamide in[2,3]-sigmatropic rearrangement.The mechanism studies reveal that the key to asymmetric rearrangement of allylic selenium ylides is the transfer of chirality from the stable chiral selenium to the carbon of the product.A feasible catalytic cycle is proposed as well.展开更多
The first investigation on catalytic asymmetric [2,3]-sigmatrop-ic rearrangement of sulfur ylides generated from carbenoids and allenic phenyl sulfide was carried out. Up to 55% ee value was obtained.
背景:3D打印技术可根据患者实际病情和治疗需求设计构建模型、手术导板和个性化植入体或固定物,在创伤性骨折修复中展示了巨大的应用前景。目的:综述3D打印技术在创伤性骨折中的应用。方法:检索Web of science、PubMed和中国知网数据库2...背景:3D打印技术可根据患者实际病情和治疗需求设计构建模型、手术导板和个性化植入体或固定物,在创伤性骨折修复中展示了巨大的应用前景。目的:综述3D打印技术在创伤性骨折中的应用。方法:检索Web of science、PubMed和中国知网数据库2020-2024年发表的创伤骨科领域3D打印技术应用的相关文献,英文检索词为“traumatic fracture,3D printing technology,digital model,surgical guide”,中文检索词为“创伤性骨折,3D打印技术,数字模型,手术导板”,经筛选和分析,最终纳入60篇文献进行分析。结果与结论:①创伤性骨折是各种致伤因素导致的骨骼连续性中断和完整性破坏的骨折现象,以可靠方案提高复位愈合效果,已成为骨外科相关研究领域亟需解决的热点问题;②3D打印技术是以数字模型数据为基础的,运用粉末状金属或聚合物等可黏合成型材料以立体光刻、沉积建模和光聚合物喷射等形式制造满足需求三维实体的技术,在数字骨科生物医学领域应用广泛;③3D打印技术在疾病诊断、术前规划、重建骨折三维模型、定制骨科植入体、定制固定支具及假肢、手术导板制作和骨缺损修复等方面发挥了显著的优势,可根据患者实际病情和治疗需求设计构建模型、手术导板和个性化植入体或固定物,为创伤性骨折的治疗提供了新的思路。展开更多
基金The authors acknowledge financial support from the National Natural Science Foundation of China(grant nos.21625205 and 21772127).
文摘Organoselenium compounds,due to their high structural diversity,special function,and biological activities,have drawn attention in synthetic chemistry.Herein,a novel example of chiral N,N′-dioxide/cobalt(Ⅱ)complex catalyzed asymmetric[2,3]-sigmatropic rearrangement of allylic selenides withα-diazo pyrazoleamides is disclosed,which represents a highly efficient approach to optically active selenides bearing a quaternary C–Se stereocenter.Most of the reactions proceed with 0.5–2 mol%catalyst loading in an inert-free gas atmosphere,and a wealth of chiral selenides are obtained in up to 99% yield and 97%enantiomeric excess(ee).The control experiments demonstrate the high reactivity of allylic selenides,as well as the conspicuous superiority of chiral N,N′-dioxide ligand andα-diazo pyrazoleamide in[2,3]-sigmatropic rearrangement.The mechanism studies reveal that the key to asymmetric rearrangement of allylic selenium ylides is the transfer of chirality from the stable chiral selenium to the carbon of the product.A feasible catalytic cycle is proposed as well.
基金Project supported by the National Natural Science Foundation of China(Nos.20225205 and 20172002),State Key Laboratory of Elemento-Organic Chemistry of Nankai University and by Trans-Century Training Programme foundation for the Talents by Ministry of Edu
文摘The first investigation on catalytic asymmetric [2,3]-sigmatrop-ic rearrangement of sulfur ylides generated from carbenoids and allenic phenyl sulfide was carried out. Up to 55% ee value was obtained.
