一种环境友好且操作简单的一锅法,用于在水中使用 AgI 作为催化剂从邻炔醛和芳胺中区域选择性串联合成多种取代的稠合苯并咪唑并 [2,1-a] 异喹啉、萘啶、噻吩并吡啶和喹喔啉被描述。该反应显示在更具亲电性的炔基碳上形成了选择性的 N-C 键,从而产生了区域选择性的 6-endo-dig 环化产物,产率很好。所提出的合成稠合杂环的机理途径是在环 B 之前形成环 A,环 B 是通过氮对炔基碳的第二次分子内攻击形成的,得到了分离的中间体 U 和环化产物 5a 的机械实验和 X 射线晶体学研究的支持。对比实验表明,分子内亲核攻击的可行性高于外部亲核试剂的分子间攻击。这种催化的绿色方案已有效地应用于水中的双串联环化。
Synthesis of cyclopentaquinolinone and cyclopentapyridinone from <i>ortho</i>-alkynyl-<i>N</i>-arylaldehyde <i>via</i> superbase-promoted C–N, C–O and C–C bond formation
作者:Kapil Mohan Saini、Rakesh K. Saunthwal、Sushmita、Akhilesh K. Verma
DOI:10.1039/d0ob01281e
日期:——
and cyclopentapyridinones via C–N, C–C, and CO bond formation. Contrary to the traditional approaches of ringclosures, a different mode of annulation is disclosed. The protocol involves the in situ generations of imine intermediate followed by potassium hydroxide-promoted intramolecular cyclization and subsequent dimethyl sulfoxide induced dehydrogenation leads to the formation of N-heterocycles. X-ray
Dual function of carbon tetrachloride: synthesis of chlorinated heterocycles
作者:Shiv Kumar、Rakesh K. Saunthwal、Kapil M. Saini、Akhilesh K. Verma
DOI:10.1039/c9cc04746h
日期:——
An efficient tandem approach to invent highly chlorinated and structurally diversified dihydropyridine fused heterocycles from easily accessible ortho-alkynylaldehydes and primary amines under metal-free conditions via four sequential bond formations is described. The proposed tandem route proceeds via a carbon tetrachloride-mediated 6-endo-dig ring closure followed by nucleophilic attack of the trichloromethyl
An efficient approach for the facile synthesis of phosphonylated 1,3-dihydrofuro[3,4-b]quinolines and dihydrofuro[3,4-b]pyridines is developed. Reaction proceeds by the formation of new C–P and C–O bonds affording Z-selective phosphonylated products at room temperature. Diphenylphosphine oxides and dialkyl phosphites are explicitly incorporated into the carbonyl carbon of o-alkynylaldehydes in good
开发了一种轻松合成膦酰化1,3-二氢呋喃并[3,4-b]喹啉和二氢呋喃并[3,4-b]吡啶的有效方法。反应通过形成新的 C-P 和 C-O 键进行,在室温下提供 Z-选择性膦酰化产物。二苯基氧化膦和亚磷酸二烷基酯以良好至优异的产率明确地结合到邻炔醛的羰基碳中。该反应条件温和,底物范围广泛,并在银催化剂存在下形成三个新键。机理研究表明,反应通过离子途径以 5-exo-dig 方式进行,产生 Z 选择性产物,并通过 X 射线晶体学研究得到验证。对所选化合物的光物理研究揭示了 455 nm 范围内的发射最大值。
On Water: Silver-Catalyzed Domino Approach for the Synthesis of Benzoxazine/Oxazine-Fused Isoquinolines and Naphthyridines from<i>o</i>-Alkynyl Aldehydes
作者:Akhilesh K. Verma、Deepak Choudhary、Rakesh K. Saunthwal、Vineeta Rustagi、Monika Patel、Rakesh K. Tiwari
DOI:10.1021/jo4009639
日期:2013.7.5
An operationally simple domino approach for the silver-catalyzed synthesis of oxazine/benzoxazine-fused isoquinolines 5a-q and naphthyridines 6a-v by the reaction of o-alkynyl aldehydes 3a-aa with amines having embedded nucleophiles 4a-d under mild reaction condition in water is described. The reaction shows selective C-N bond formation on the more electrophilic alkynyl carbon resulting in the formation of 6-endo-dig cyclized product. The competitive experiments show the viability of an intramolecular nucleo philic attack over an intermolecular attack of the external nucleophile. This methodology accommodates wide functional group variation, which proves to be useful for structural and biological assessment.
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