Rh-Catalyzed Conjugate Addition of Arylzinc Chlorides to Thiochromones: A Highly Enantioselective Pathway for Accessing Chiral Thioflavanones
作者:Ling Meng、Ming Yu Jin、Jun Wang
DOI:10.1021/acs.orglett.6b02453
日期:2016.10.7
A highly efficient asymmetric synthesis of chiral thioflavanones is developed via conjugateaddition of arylzinc reagents to thiochromones using Rh(COD)Cl2/(R)-3,4,5-MeO-MeOBIPHEP catalyst. This method overcomes catalyst poisoning and substrate inertness and affords a series of chiral thioflavanones (2-arylthiochroman-4-ones) in good yields (up to 91% yield) with excellent ee values (up to 97% ee)
Cu-Catalyzed Conjugate Addition of Grignard Reagents to Thiochromones: An Enantioselective Pathway for Accessing 2-Alkylthiochromanones
作者:Qingxiong Yang、Jun Wang、Shihui Luo、Ling Meng
DOI:10.1055/s-0037-1610225
日期:2018.9
The enantioselective incorporation of alkyl groups in thiochromones was realized for the first time by a Cu/(R,S)-PPF-P t Bu2-catalyzed conjugate addition of Grignardreagents to thiochromones. With this method, a series of 2-methylthiochromanones were obtained in good yields (up to 96% yield) with moderate-to-good ee values (up to 87% ee). The established method expedites the synthesis of a large
通过Cu/(R,S)-PPF-P t Bu2 催化的格氏试剂与硫色酮的共轭加成,首次实现了烷基在硫色酮中的对映选择性掺入。使用这种方法,以良好的收率(最高 96% 的收率)获得了一系列 2-甲基硫代色满酮,其 ee 值中等至良好(最高 87% ee)。已建立的方法加速了大型手性硫代色满酮库的合成,以用于进一步的合成应用和生物学研究。
Site-Selective Acceptorless Dehydrogenation of Aliphatics Enabled by Organophotoredox/Cobalt Dual Catalysis
cobaloxime to produce olefins and H2. This operationally simple method enables direct dehydrogenation of readily available chemical feedstocks to diversely functionalized olefins. For example, we demonstrate, for the first time, the oxidant-free desaturation of thioethers and amides to alkenyl sulfides and enamides, respectively. Moreover, the system’s exceptional siteselectivity and functional group
脂肪族催化脱氢 (CDA) 在有机合成中的价值在很大程度上仍未得到充分探索。已知的均相 CDA 系统通常需要使用牺牲氢受体(或氧化剂)、贵金属催化剂和苛刻的反应条件,因此将大多数现有方法限制为非或低官能化烷烃的脱氢。在这里,我们描述了一种可见光驱动的双催化剂系统,该系统由廉价的有机光氧化还原和贱金属催化剂组成,用于室温、无受体 CDA (Al-CDA)。该过程由光激发的 2-氯蒽醌引发,涉及脂肪族的 H 原子转移 (HAT) 形成烷基自由基,然后与钴肟反应生成烯烃和 H 2. 这种操作简单的方法能够将容易获得的化学原料直接脱氢成多种官能化的烯烃。例如,我们首次证明了硫醚和酰胺在无氧化剂条件下分别脱饱和为烯基硫醚和烯酰胺。此外,14 种生物相关分子和药物成分的后期脱氢和合成说明了该系统卓越的位点选择性和官能团耐受性。机理研究揭示了双重 HAT 过程,并提供了对反应性和位点选择性起源的见解。
Synthesis of benzothiazonine by rhodium-catalyzed denitrogenative transannulation of 1-sulfonyl-1,2,3-triazole and thiochromone
作者:Saygbechi T. Jablasone、Zihang Ye、Shengguo Duan、Ze-Feng Xu、Chuan-Ying Li
DOI:10.1039/d1ob00419k
日期:——
A facile synthesis of functionalized benzothiazonine was achieved by rhodium-catalyzed denitrogenative annulation of easily available 1-sulfonyl-1,2,3-triazole and thiochromone.
Palladium-Catalyzed Synthesis of (<i>Z</i>)-3-Arylthioacrylic Acids and Thiochromenones
作者:Thiruvengadam Palani、Kyungho Park、Kwang Ho Song、Sunwoo Lee
DOI:10.1002/adsc.201201106
日期:2013.4.15
reaction of aryl halides, sodium sulfide pentahydrate (Na2S⋅5 H2O), and propiolic acid in the presence of 2.5% bis(triphenylphosphine)palladium chloride [Pd(PPh3)2Cl2], 5% 1,4‐bis(diphenylphosphino)butane (dppb) and 2 equivalents of 1,8‐diazabicycloundec‐7‐ene (DBU) produces stereoselectively (Z)‐3‐arylthioacrylic acids in good yields. A study of the reaction pathway suggested that the CS bond formation