2-(E -2-硝基乙烯基)-1 H-吡咯(2a)与1,4-苯醌的Diels-Alder反应得到所需的苯并[ e ]吲哚-6,9(3 H)-二酮(4a)。从N-(或1)-甲基化合物(2b)得到的已知N-甲基化合物(4b)的产率为10%,而产率为26%(86%[5] )。用苯基磺酰基(2c)保护2a的氮得到9%的相应的N-(或3)-苯基磺酰基化合物(4c)。2b的反应用1,4-萘醌的苯甲酸酯的产率为6%(浓度为64%[5]),已知的3-甲基萘[2,3 - e ]-吲哚-6,9(3H)-二酮(6)。2-(E -2-硝基乙烯基)呋喃(8a)的反应产生少量所需的萘并[2,1 - b ]呋喃-6,9-二酮(9a),通过比较其NMR谱图可知的4b。2-(E -2-硝基乙烯基)噻吩(8b)的相应反应得到萘并[2,1 - b ]噻吩-6,9-二酮(9b)的产率为4%),先前制备过程以24%的收率[12],
A method of making chlorins comprises the steps of reacting (e.g. condensing) a dipyrrin western half intermediate with an eastern half intermediate to form a tetrahydrobilene, and then cyclizing the tetrahydrobilene to form a chlorin. Intermediates including tetrahydrobilenes useful in such reactions are also described.
One-Step, Effective, and Cascade Syntheses of Highly Functionalized Cyclopentenes with High Diastereoselectivity
作者:Suman Alishetty、Hong-Pin Shih、Chien-Chung Han
DOI:10.1021/acs.orglett.8b00510
日期:2018.5.4
Tetrabutylammoniumfluoride works as an effective organocatalyst for the cycloaddition between phenacylmalononitriles and electron-deficient olefins (having substituent groups of NO2, CHO, and COR), providing a facile synthetic route to versatile multifunctionalized cyclopentenes having an allylic quaternary carbon center bearing both cyano and carboxamide groups with high yields and high diastereoselectivity
Sulfinate and Carbene Co‐catalyzed Rauhut–Currier Reaction for Enantioselective Access to Azepino[1,2‐
<i>a</i>
]indoles
作者:Xingxing Wu、Liejin Zhou、Rakesh Maiti、Chengli Mou、Lutai Pan、Yonggui Robin Chi
DOI:10.1002/anie.201810879
日期:2019.1.8
A carbene and sulfinate co‐catalyzed intermolecular Rauhut–Currierreaction between enals and nitrovinyl indoles is disclosed. The carbene catalyst activates the enal and the sulfinate co‐catalyst activates the nitrovinyl indole. Both activation processes are realized via the formation of covalent bonds between the catalysts and substrates to generate catalyst‐bound intermediates. The dual catalytic
揭示了烯与亚硝基吲哚之间的卡宾和亚磺酸盐共催化的分子间Rauhut-Currier反应。卡宾催化剂活化烯醛,亚磺酸盐助催化剂活化硝基乙烯基吲哚。两种活化过程都是通过在催化剂和底物之间形成共价键以生成与催化剂结合的中间体来实现的。双重催化反应可提供具有出色立体选择性的氮杂环庚烷[1,2- a ]吲哚产物。我们的研究表明,亚磺酸盐作为一种有效的亲核催化剂,可以在活化电子不足的烯烃以进行不对称反应中发挥独特作用。这种双重催化方法也应鼓励对亚磺酸盐和卡宾催化剂的未来开发进行新的反应。
Asymmetric Synthesis of Pyrroloindolones by N-Heterocyclic Carbene Catalyzed [2+3] Annulation of α-Chloroaldehydes with Nitrovinylindoles
作者:Qijian Ni、Huan Zhang、André Grossmann、Charles C. J. Loh、Carina Merkens、Dieter Enders
DOI:10.1002/anie.201305957
日期:2013.12.16
NHC‐enolate plus 3: N‐heterocyclic carbenes (NHCs) serve as organocatalysts for the [2+3] annulation of nitrovinylindoles with α‐chloroaldehydes via an intermediate azolium enolate. The method provides trans‐disubstituted pyrroloindolones with good yields and excellent diastereo‐ and enantioselectivities. Further transformations lead to tetracyclic pyrrolo[1,2‐a]indoles with potential psychotropic
NHC-烯酸酯加3:N-杂环卡宾(NHCs)用作有机催化剂,通过中间的偶氮烯醇烯酸酯与α-氯醛进行[2 + 3]的硝基乙烯基吲哚环化。该方法提供了具有良好收率和出色的非对映和对映选择性的反式-双取代吡咯并吲哚酮。进一步的转化导致具有潜在精神活性和其他生物活性的四环吡咯并[1,2- a ]吲哚。