An efficient, eco-friendly, and highly convergent one-pot route to privileged thiazoloquinolinone derivatives has been developed via four-component cascade coupling (4CCC) of α-enolic dithioesters, cysteamine/2-aminothiophenols, aldehydes, and cyclic 1,3-diketones in recyclable [EMIM][EtSO4] ionicliquid at room temperature for the first time. The reaction proceeds via a N,S-acetal formation, Knoevenagel
Site‐Specific S‐Allylation of α‐Enolic Dithioesters with Morita‐Baylis‐Hillman Acetates at Room Temperature: Precursor for Thiopyrans
作者:Sonam Soni、Suvajit Koley、Monish A. Ansari、Maya Shankar Singh
DOI:10.1002/adsc.201900580
日期:2019.9.3
An efficient one‐pot allylic alkylation of α‐enolic dithioesters (DTEs) with Morita‐Baylis‐Hillman (MBH) acetates has been devised in ethanol at room temperature. The reaction being site‐selective provided S‐allylated product exclusively with trace amount of C‐allylated one. Remarkably, some of the S‐allylated product undergoes [3,3]‐sigmatropic rearrangement to C‐allylated one under ethanol reflux
straightforward approach for the chemodivergent synthesis of quinolines is described through site‐selective coupling of ortho‐aminoaryl ketones with α‐enolic dithioesters (DTEs) under solvent‐free conditions. The operationally and user‐simple one‐pot methodology is based on the trifunctional nature of DTEs. Both the carbonyl and the thiocarbonyl moiety in α‐enolic dithioesters were employed for the efficient
Metal‐ and Catalyst‐Free One‐Pot Cascade Coupling of α‐Enolic Dithioesters with in situ Generated 4‐Chloro‐3‐formylcoumarin: Access to Thioxothiopyrano[3,2‐
<i>c</i>
]chromen‐5(2
<i>H</i>
)‐ones
作者:Dhananjay Yadav、Monish A. Ansari、Mitilesh Kumar、Maya Shankar Singh
DOI:10.1002/adsc.201901180
日期:2020.2.6
for the synthesis of a specific class of 2‐thioxothiopyrano[3,2‐c] chromen‐5(2H)‐ones has been devised by the cross‐coupling of 4‐hydroxycoumarin and α‐enolic dithioesters under metal‐ and additive‐free conditions in open air. The reaction proceeds via in situ generation of 4‐chloro‐3‐formylcoumarin followed by consecutive Michael‐type addition/intramolecular cyclization/ eliminationcascade, enabling
通过4-羟基香豆素和α-羟基香豆素的交叉偶联,设计出了一种有效且可行的一锅法,用于合成特定类别的2-thioxothiopyrano [3,2 - c ] chromen -5(2 H)-ones。不含金属和添加剂的露天条件下的烯醇二硫酯。反应通过原位生成4-氯-3-甲酰基香豆素进行,然后连续进行Michael型加成/分子内环化/消除级联反应,从而通过连续形成C-C和C形成香豆素骨架上的噻喃-2-硫酮环。 CS键。值得注意的是,该功能策略的附加特性是良性条件,原子经济性和对广泛功能基团的承受能力。
Copper-Catalyzed One-Pot Cross-Dehydrogenative Thienannulation: Chemoselective Access to Naphtho[2,1-<i>b</i>]thiophene-4,5-diones and Subsequent Transformation to Benzo[<i>a</i>]thieno[3,2-<i>c</i>]phenazines
A facile, cost-effective, and highly efficient copper-catalyzed, TEMPO-mediated straightforward synthesis of 2,3-disubstituted naphtho[2,1-b]thiophene-4,5-diones has been achieved via cross-dehydrogenative thienannulation. The reaction proceeded via in situ generated naphthalene-1,2-diones by dearomatization of β-naphthols, followed by oxidative heteroannulation with α-enolic dithioesters chemoselectively
通过交叉脱氢噻吩鎓制得了一种简便,经济高效且高效的铜催化,TEMPO介导的2,3-二取代萘并[ 2,1- b ]噻吩-4,5-二酮直接合成方法。反应通过原位生成的萘-1,2-二酮进行,方法是将β-萘酚脱芳香化,然后在敞口烧瓶中用α-烯醇二硫代酯进行化学选择性氧化杂化。此外,萘并[2,1 - b ]噻吩-4,5-二酮与邻苯二胺一起进行1-脯氨酸催化的交叉脱水偶联,从而使五环苯并[ a ]噻吩并[3,2- c在无溶剂条件下,[[]]吩嗪具有良好的收率。控制实验很好地支持了该级联反应序列的机械原理。