- The aza-hexadehydro-diels-alder reaction
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The generation of pyridynes from diyne nitriles is reported. These cyano-containing precursors are analogues of the triyne substrates typically used for the hexadehydro-Diels-Alder (HDDA) cycloisomerization reactions that produce ring-fused benzynes. Hence, the new processes described represent aza-HDDA reactions. Depending on the location of the nitrile, either 3,4-pyridynes (from 1,3-diynes containing a tethered cyano group) or 2,3-pyridynes (from 1-cyanoethyne derivatives containing a tethered alkyne) are produced. In situ trapping of these reactive intermediates leads to highly substituted and functionalized pyridine derivatives. In several instances, unprecedented pyridyne trapping reactions are seen. Differences in reaction energetics between the aza-HDDA substrates and that of their analogous HDDA (triyne) substrates are discussed.
- Thompson, Severin K.,Hoye, Thomas R.
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- Construction of 2-Arylbenzo[4,5]thieno[2,3-d]thiazole Skeleton via CuCl/S-Mediated Three-Component Reaction
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An exclusive thiophene-fused polycyclic I-conjugated 2-arylbenzo[4,5]thieno[2,3-d]thiazole skeleton was constructed via a one-pot CuCl-mediated three-component reaction, using 2-(2-bromophenyl)acetonitrile and aromatic aldehydes as substrates and elementa
- Zhang, Wei,Tao, Shanqing,Ge, Huaibin,Li, Qiao,Ai, Zhenkang,Li, Xiaoxian,Zhang, Beibei,Sun, Fengxia,Xu, Xiaqing,Du, Yunfei
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supporting information
p. 448 - 452
(2020/02/04)
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- A high-yielding modular access to the lamellarins: Synthesis of lamellarin G trimethyl ether, lamellarin η and dihydrolamellarin η
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A deprotonated α-aminonitrile serves as a key intermediate in a highly efficient (95 % per step on average; see scheme) modular synthetic approach to the lamellarin alkaloids. Its reaction with an α,β- unsaturated aldehyde forms the central pyrrole ring in a one-pot procedure. The construction of the fused pentacyclic skeleton is completed by a microwave-assisted Ullmann-type lactone formation.
- Imbri, Dennis,Tauber, Johannes,Opatz, Till
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supporting information
p. 15080 - 15083
(2013/11/06)
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- Determining the scope of the lanthanide mediated, sequential hydroamination/C-C cyclization reaction: Formation of tricyclic and tetracyclic aromatic nitrogen heterocycles
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The scope of the lanthanide mediated, sequential hydroamination/C-C cyclization reaction was determined for the formation of tricyclic and tetracyclic aromatic nitrogen heterocycles. An array of ring sizes was explored to determine the diastereoselectivity. The electronic characteristics of the aromatic ring was also varied to determine how it affected the cascade reaction. It was found that the benzo[a]quinolizine and the pyrido[2,1,a]isoindolizine ring systems formed with the highest diastereoselectivity (>20:1), regardless of the electronic characteristics of the aromatic ring. Additionally, a tetracyclic indole nitrogen heterocycle was formed with a 2.3:1 diastereomeric ratio. A novel procedure for substrate preparation is also presented.
- Molander, Gary A.,Pack, Shawn K.
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p. 10581 - 10591
(2007/10/03)
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- BENZOPHENANTHRIDINES V. INVESTIGATION OF THE RODIONOV-SUVOROV SCHEME. SYNTHESIS OF 3,3-DIETHOXYCARBONYL-2-(3,4-DIMETHOXYPHENYL)-6,7-DIMETHOXY-1-TETRALONE
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Triethyl 1,3-bis(3,4-dimethoxyphenyl)propane-1,2,2-tricarboxylate was synthesized by the alkylation of the lithium enolate of ethyl homoveratrate with α-bromo(3,4-dimethoxybenzyl)malonic ester.It was converted by intramolecular acylation, catalyzed by BF3
- Kyong, Dao Hung,Sladkov, V. I.,Suvorov, N. N.
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p. 1732 - 1738
(2007/10/02)
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