制备了一系列的烯丙基酰胺,并研究了它们在金催化下的环化反应。观察到六元环1,3-恶嗪的形成。源自亚丙基的远端CC双键的分子内加氢胺化的二氢吡咯是次要的副产物。通过原位31 P NMR光谱进行的机理研究表明,在每种情况下,转化过程中仅增加了一种。通过对不同烯丙基金(I)物种的计算研究,可以将其指定为在空间位阻较少的亚甲基末端带有金催化剂的σ-烯丙基金。该中间体的区域特异性氘化脱氢证实了催化循环最后一步的S E '型机制。
A catalytic highly enantioselective allene approach to oxazolines
作者:Hongwen Luo、Zheng Yang、Weilong Lin、Yangguangyan Zheng、Shengming Ma
DOI:10.1039/c7sc04079b
日期:——
heterocyclic compounds. However, catalytic enantioselective syntheses are very limited. Here, a highly enantioselective palladium-catalyzed coupling-cyclization of readily available N-(buta-2,3-dienyl) amides with aryl or 1-alkenyl iodides has been developed for the asymmetric construction of oxazoline derivatives. Many synthetically useful functional groups are tolerated in this reaction. The absolute configuration
Efficient synthesis of N-(buta-2,3-dienyl) amides from terminal N-propargyl amides and their synthetic potential towards oxazoline derivatives
作者:Bo Chen、Nan Wang、Wu Fan、Shengming Ma
DOI:10.1039/c2ob26291f
日期:——
A series of N-allenyl amides was prepared conveniently from N-propargyl amides in good to excellent yields via a modified procedure developed in this group. The palladium-catalyzed coupling–cyclization of these prepared N-allenyl amides in the presence of organic iodides has been developed affording the oxazoline derivatives efficiently.
Cobaltaelectro-Catalyzed C–H Annulation with Allenes for Atropochiral and <i>P</i>-Stereogenic Compounds: Late-Stage Diversification and Continuous Flow Scale-Up
作者:Ye Lin、Tristan von Münchow、Lutz Ackermann
DOI:10.1021/acscatal.3c02072
日期:2023.7.21
metallaelectro-catalyzed C–Hactivation has been identified as an increasingly viable strategy to access valuable organic molecules in a resource-economic fashion under exceedingly mild reaction conditions. However, the development of enantioselective 3d metallaelectro-catalyzed C–Hactivation is very challenging and in its infancy. Here, we disclose the merger of cobaltaelectro-catalyzed C–Hactivation with asymmetric
Copper(II)-Promoted Cyclization/Difunctionalization of Allenols and Allenylsulfonamides: Synthesis of Heterocycle-Functionalized Vinyl Carboxylate Esters
作者:Barbara J. Casavant、Zainab M. Khoder、Ilyas A. Berhane、Sherry R. Chemler
DOI:10.1021/acs.orglett.5b02833
日期:2015.12.18
A unique method to affect intramolecular aminooxygenation and dioxygenation of allenols and allenylsulfonamides is described. These operationally simple reactions occur under neutral or basic conditions where copper(II) carboxylates serve as reaction promoter, oxidant, and carboxylate source. Moderate to high yields of heterocycle-functionalized vinyl carboxylate esters are formed with moderate to high levels of diastereoselectivity. Such vinyl carboxylate esters could serve as precursors to alpha-amino and alpha-oxy ketones and derivatives thereof.
Studies on Electrophilic Cyclization of<i>N</i>-(Buta-2,3-dienyl)amides with<i>N</i>-Bromosuccinimide and its Applications
作者:Nan Wang、Bo Chen、Shengming Ma
DOI:10.1002/adsc.201300959
日期:2014.2.10
AbstractAn efficient protocol for the synthesis of oxazoline and bisoxazoline derivatives via electrophilic cyclization of N‐(buta‐2,3‐dienyl)amides with N‐bromosuccinimide (NBS) at room temperature has been developed. Synthetic transformations of the obtained oxazolines have been successfully performed due to the presence of vinyl bromide units comprising an elimination reaction and a copper(I)‐catalyzed CN coupling reaction using diethylamine (Et2NH) as the ligand.magnified image