Silver-Catalyzed Tandem Synthesis of Naphthyridines and Thienopyridines via Three-Component Reaction
摘要:
An efficient approach for the silver-catalyzed regioselective tandem synthesis of highly functionalized 1,2-dihydorbenzo[1,6]naphthyridines 6a-z and 7a-e by the reaction of ortho-alkynylaldehydes 3a-n with amines 4a-d and ketones 5a-c/active methylene compounds 5d-g, under mild reaction conditions, is described. The scope of the developed chemistry was successfully extended for the direct synthesis of 1,2-dihydorbenzo[4,5]thieno[2,3-c]pyridines 8a-e, which is known as the sulfur analogue of beta-carbolines. Naphthyridines 6a-z and thienopyridines 8a-e were obtained via dual activation concept using L-proline as organocatalyst; however, naphthyridines 7a-e were synthesized without using organocatalyst. The reaction shows selective N-C bond formation on the more electrophilic alkynyl carbon, resulting in the regioselective 6-endo-digcyclized products. Reactivity behavior of electron-deficient and electron-rich ortho-alkynylaldehydes in the synthesis of naphthyridines and thienopyridine by three-component reaction is supported by the control experiment.
Site-Selective Electrophilic Cyclization and Subsequent Ring-Opening: A Synthetic Route to Pyrrolo[1,2-<i>a</i>]quinolines and Indolizines
作者:Trapti Aggarwal、Sonu Kumar、Devendra K. Dhaked、Rakesh K. Tiwari、Prasad V. Bharatam、Akhilesh K. Verma
DOI:10.1021/jo3015374
日期:2012.10.5
An efficient strategy for the synthesis of pyrrolo[1,2-a]quinolines and indolizines from pyranoquinolines via site-selective electrophilic cyclization and subsequent opening of pyran ring using silver/iodine under mildreaction conditions is described. This approach involves the preferential attack of the pyridyl nitrogen over aryl ring and leads to the formation of 5-endo-dig cyclized products. Quantum
描述了一种通过位点选择性亲电环化从吡喃并喹啉合成吡咯并[1,2- a ]喹啉和吲哚嗪的有效策略,随后在温和的反应条件下使用银/碘打开吡喃环。这种方法涉及的吡啶基的氮的优先攻击过的芳环,并导致5-地层内切-挖环化产物。C–N(ΔE a = 9.01 kcal / mol)和C–C(ΔE a为了使观察到的位点选择性合理化,进行= 31.31kcal / mol)的键形成。通过X射线晶体学研究证实了产物的结构。通过Pd催化的交叉偶联反应,通过亲电碘化反应生成的碘取代的化合物进一步多样化。
Silver-catalyzed regioselective synthesis of acridines, quinolines, and naphthalenes from 3-(2-alkynyl)aryl-β-ketoesters
general synthetic method for a wide range of medicinally useful 2-carboxylate derivatives of acridinols, quinolinols, and naphthalenols has been developed via silver-catalyzed electrophilic cyclization of 3-(2-alkynyl)aryl-β-ketoesters. The designed reaction involved selective C–C bond formation on more electrophilic alkynyl carbon, which resulted in the regioselective 6-endo-dig cyclized product, as confirmed
Iodine-Mediated Solvent-Controlled Selective Electrophilic Cyclization and Oxidative Esterification of <i>o</i>-Alkynyl Aldehydes: An Easy Access to Pyranoquinolines, Pyranoquinolinones, and Isocumarins
作者:Akhilesh K. Verma、Vineeta Rustagi、Trapti Aggarwal、Amit P. Singh
DOI:10.1021/jo101526b
日期:2010.11.19
provides pyrano[4,3-b]quinolines 4a−f, via formation of cyclic iodonium intermediate Q; however, using alcohols as a solvent as well as nucleophile, o-alkynyl esters 5a−y were obtained selectively in good to excellent yields via formation of hypoiodide intermediate R. Subsequently, o-alkynyl esters were converted in to pyranoquinolinones 6a−i and isocoumarin 6j by electrophilic iodocyclization. This
Iodine-catalyzed and solvent-controlled selective electrophilic cyclization and oxidative esterification of ortho-alkynyl aldehydes
作者:Akhilesh Kumar Verma、Trapti Aggarwal、Vineeta Rustagi、Richard C. Larock
DOI:10.1039/b927185f
日期:——
4-Iodo-pyrano[4,3-b]quinolines and ortho-alkynyl esters were synthesized selectively from ortho-alkynyl aldehydes by an iodine-catalyzed and solvent controlled reaction.
Triple‐Bond Directed Csp
<sup>2</sup>
−N Bond Formation with
<i>N</i>
‐Fluorobenzenesulfonimide as Aminating Source: One‐Step Transformation of Aldehydes into Amines
作者:Sushmita、Trapti Aggarwal、Norio Shibata、Akhilesh K. Verma
DOI:10.1002/chem.201903495
日期:2019.12.13
amination of ortho‐alkynyl quinoline/pyridine aldehydes using N‐fluorobenzenesulfonimide as nitrogen source under mild reaction conditions has been described. The designed reaction strategy was triggered by trapping of fluorine by base with subsequent attack of bis(phenylsulfonyl)‐λ2‐azane on the carbonyl carbon of a heterocycle, which was gradually converted into the corresponding amine through a Curtius