报道了一步一步制备8,10a-环氧吡啶并[2,1- a ]异吲哚及其7-羧酸衍生物的方法。关键的合成步骤包括N-糠基丙烯酰胺的分子内exo -Diels-Alder反应(IMDAF),它是由2-糠基哌啶-4-酮和α,β-不饱和酸酐原位产生的。标题化合物的合成可以在温和条件下进行,具有很高的区域和立体选择性。从马来酸酐和菠菜碱衍生物合成4,9,11a-环氧咪唑并[4',5':3,4]吡啶[2,1- a ]异吲哚-8-羧酸已成功采用了相同的策略– 4 -(2-呋喃基)-4,5,6,7-四氢-3 H-咪唑[4,5- c]吡啶。J.杂环化学。(2010)。
报道了一步一步制备8,10a-环氧吡啶并[2,1- a ]异吲哚及其7-羧酸衍生物的方法。关键的合成步骤包括N-糠基丙烯酰胺的分子内exo -Diels-Alder反应(IMDAF),它是由2-糠基哌啶-4-酮和α,β-不饱和酸酐原位产生的。标题化合物的合成可以在温和条件下进行,具有很高的区域和立体选择性。从马来酸酐和菠菜碱衍生物合成4,9,11a-环氧咪唑并[4',5':3,4]吡啶[2,1- a ]异吲哚-8-羧酸已成功采用了相同的策略– 4 -(2-呋喃基)-4,5,6,7-四氢-3 H-咪唑[4,5- c]吡啶。J.杂环化学。(2010)。
A Two-Stage Synthesis of 8,10a-Epoxypyrido[2,1-a]isoindoles: Stereochemistry of the [4+2] Cycloaddition of Maleic Anhydride with 2,6-Difurylpiperidin-4-ones
A new straightforward synthesis of 8,10a-epoxypyrido[2,1-a]isoindoles and their 7-carboxylic acids from 2,6-difuryl-substituted piperidin-4-ones and maleic anhydride or acryloyl chloride via the intramolecular Diels-Alder reaction has been demonstrated. It has been shown that a one-stage synthesis of the title compounds can be performed under mild conditions and with high levels of regio- and stereoselectivity
通过分子内Diels-Alder反应,由2,6-二呋喃基取代的哌啶-4-酮与马来酸酐或丙烯酰氯直接合成8,10a-环氧吡啶并[2,1- a ]异吲哚及其7-羧酸已经证明。已经表明,标题化合物的一步合成可以在温和的条件下进行,并且具有从容易获得的2-呋喃基哌啶中高水平的区域选择性和立体选择性。 分子内Diels-Alder呋喃反应-IMDAF-立体选择性合成-呋喃-2,6-二呋喃哌啶-4-酮-吡啶并[2,1- a ]异吲哚
Chemoselectivity of [4 + 2] cycloaddition in N-maleyl- and N-allyl-2,6-difurylpiperidin-4-ones
作者:F. I. Zubkov、E. V. Nikitina、V. P. Zaytsev、V. N. Khrustalev、R. A. Novikov、R. S. Borisov、A. V. Varlamov
DOI:10.1007/s10593-012-1057-4
日期:2012.8
On the basis of a transition state conformation analysis, an attempt was made to explain the high chemoselectivity of intramolecular [4 + 2] cycloaddition in 3-alkyl-2,6-difuryl-N-maleylpiperidin-4-ones. It was shown that the thermal Diels-Alder reaction in these piperidine derivatives takes place through the "boat" conformation and leads to the formation of hydrogenated 1-alkyl-4-(2-furyl)-2H-8,10a-epoxy-pyrido[2,1-a]isoindol-2-ones. The alternative regioisomers, 3-alkyl-4-(2-furyl)-2H-8,10a-epoxy-pyrido[2,1-a]isoindol-2-ones, are hardly formed at all. At the same time, the intramolecular Diels-Alder reaction in the isostructural 3-alkyl-N-allyl-2,6-difurylpiperidin-4-ones, takes place non-regioselectively from the "chair" conformation.