Catalytic asymmetric hydrogenation of N-Boc-protected pyrroles proceeded with high enantioselectivity by using a ruthenium catalyst modified with a trans-chelating chiral bisphosphine PhTRAP. The ruthenium catalyst prepared from Ru(eta3-methallyl)2(cod) and (S,S)-(R,R)-PhTRAP in the presence of triethylamine was the most enantioselective for the asymmetric hydrogenation of methyl pyrrole-2-carboxylate
通过使用用转螯合手性双膦 PhTRAP 改性的钌催化剂,N-Boc 保护的吡咯的催化不对称氢化以高对映选择性进行。在三乙胺存在下由 Ru(eta3-methallyl)2(cod) 和 (S,S)-(R,R)-PhTRAP 制备的钌催化剂对吡咯-2-羧酸甲酯的不对称氢化具有最大的对映选择性,得到所需的 (S)-脯氨酸衍生物,其 ee 为 79%,产率为 92%。此外,在 5 位带有大取代基的 2,3,5-三取代吡咯以 93-99.7% ee 氢化。4,5-二甲基吡咯-2-羧酸酯的不对称还原仅产生全顺式异构体,并在单个过程中产生具有高度立体控制的三个手性中心。这是吡咯的第一次高度对映选择性还原。
[EN] AMIDE DERIVATIVE SERVING AS PROSTAGLANDIN EP4 RECEPTOR ANTAGONIST, AND USE THEREOF<br/>[FR] DÉRIVÉ D'AMINE SERVANT D'ANTAGONISTE DU RÉCEPTEUR EP4 DE LA PROSTAGLANDINE ET SON UTILISATION<br/>[ZH] 作为前列腺素EP4受体拮抗剂的酰胺衍生物及其用途
Synthesis of 4,5-Disubstituted Methyl 1H-Pyrrole-2-carboxylates from 3-Chloroacrylaldehydes and Hippuric Acid
作者:Alexander S. Fisyuk、Anna L. Samsonenko、Anastasia S. Kostyuchenko、Tatyana Yu. Zheleznova、Vladislav Yu. Shuvalov、Evgenii B. Uliankin、Anton L. Shatsauskas
DOI:10.1055/a-2295-8544
日期:——
was shown that the alcoholysis products of these compounds, resulting from the opening of the oxazolone ring, undergo copper-catalyzed intramolecular cross-coupling reactions with the formation of methyl 1H-pyrrole-2-carboxylates. Thus, a one-pot method was developed for the synthesis of methyl 1H-pyrrole-2-carboxylates starting from 4-(3-chloroallylidene)-2-phenyloxazol-5(4H)-ones.
酮与 DMF 和 POCl 3 的 Vilsmeier-Haack 反应生成3-氯丙烯酰甲醛,将其转化为相应的 ( Z ) -4-[( Z ) -或 ( Z ) -4-[( E ) -3-氯烯丙基 ) -2-苯基恶唑-5(4H ) -酮](吖内酯)或其异构体混合物,与丙酸酐中的马尿酸一起加热。结果表明,这些化合物的醇解产物是由恶唑酮环打开而产生的,会发生铜催化的分子内交叉偶联反应,形成1H-吡咯-2-羧酸甲酯。因此,开发了一种以4-(3-氯烯丙基)-2-苯基恶唑-5(4H)-酮为原料合成1H-吡咯-2-甲酸甲酯的一锅法。
Transition Metal-Catalyzed Synthesis of Pyrroles from Dienyl Azides
作者:Huijun Dong、Meihua Shen、Joanne E. Redford、Benjamin J. Stokes、Ashley L. Pumphrey、Tom G. Driver
DOI:10.1021/ol702262f
日期:2007.12.1
A range of 2,5-disubstituted and 2,4,5-trisubstituted pyrroles can be synthesized from dienyl azides at room temperature using catalytic amounts of Znl(2) or Rh-2(O2CC3F7)(4).
Porphyrins with exocyclic rings. 2. Synthesis of geochemically significant tetrahydrobenzoporphyrins from 4,5,6,7-tetrahydro-2H-isoindoles
作者:Donald A. May、Timothy D. Lash
DOI:10.1021/jo00044a013
日期:1992.8
Benzo- and tetrahydrobenzoporphyrins are widespread constituents of oil shales and petroleum. Although the origins of these materials are not known, a case is made for divinylchlorophyll a, a widespread pigment in marine algae, being the precursor to many of these geoporphyrins. Total syntheses of four tetrahydrobenzoporphyrins related to etioporphyrin III are described. Tetrahydroisoindoles were prepared by condensation of isocyanoacetates with 1-nitrocyclohexene in the presence of DBU or by reaction of aminomalonates with 2-formylcyclohexanone. Condensation of 3-unsubstituted 4,5,6,7-tetrahydro-2H-isoindoles 23c and 23d with (acetoxymethyl)pyrroles in the presence of Montmorillonite clay gave dipyrrylmethanes 28a and 36a in excellent yield. Hydrogenolysis of the benzyl esters and subsequent acid-catalyzed condensation with pyrrole aldehydes 37a and/or 37b gave a series of a,c-biladiene dihydrobromides. Copper(II) mediated cyclization of the a,c-biladienes 32, 33, 35, and 38, followed by demetallation with 15% sulfuric acid-trifluoroacetic acid, gave four isomeric tetrahydrobenzoporphyrins 10-13 in unusually high yield. This work provides a general route for the synthesis of these important porphyrin molecular fossils.