公开了一种布朗斯台德酸催化的串联工艺,用于获得致密官能化的铬烯基 [3,2- d ] 异恶唑,具有良好至优异的产率和非对映选择性。该程序拟涉及 1,6-共轭加成/亲电加成/双环化炔基邻苯二酚甲基化物 (o -AQMs) 的过程,原位由邻羟基炔丙醇和硝酮生成。温和的条件、良好的官能团相容性、易于放大反应和进一步的产品转化展示了其潜在的应用。
A Sc(OTf)3-catalyzed highly diastereoselective one-pot sequential [3 + 3] dipolar cycloaddition reaction of aldehyde or ketone, N-alkyl hydroxylamine, and spirocyclopropyl oxindole is developed, allowing facile construction of spirocyclic oxindole-tetrahydro-1,2-oxazines with sufficient structural diversity. The corresponding catalytic enantioselective one-pot protocol of aldehydes is also reported
An efficient [3+2] cycloaddition of nitrones and carbodiimides has been developed. This 1,3-dipolar cycloaddition features high regioselectivity, mild and metal-free conditions, excellent functional group compatibility, and a broad substrate scope. The X-ray structures of two regio-isomers confirmed the regioselectivity of this transformation.
Lewis base-catalyzed diastereoselective [3 + 2] cycloaddition reaction of nitrones with electron-deficient alkenes: an access to isoxazolidine derivatives
A Lewis base-catalyzed [3 + 2] cycloadditionreaction of nitrones with electron-deficientalkenes has been achieved under mild reaction conditions, affording various functionalized isoxazolidine derivatives as single diastereomers in moderate to excellent yields.
Synthesis of 2-arylethenesulfonyl fluorides and isoindolinones: Ru-catalyzed C–H activation of nitrones with ethenesulfonyl fluoride
作者:Tong-Tong Wang、Li-Ming Zhao
DOI:10.1039/d2cc03418b
日期:——
2-arylethenesulfonyl fluorides from nitrones and ethenesulfonyl fluoride (ESF) by the activation of the C–H bond using an inexpensive and readily available Ru-catalyst has been developed. In this process, the directing group can be concomitantly converted to an amide group. Interestingly, changing the substituent of the nitrogen of nitrones from a tert-butyl to a methyl group resulted in the formation of cyclic isoindolinones
One-Pot Synthesis of Benzo[<i>c</i>]phenanthridine Alkaloids from 7-Azabenzonorbornadienes and Aryl Nitrones
作者:Narasingan Aravindan、Masilamani Jeganmohan
DOI:10.1021/acs.orglett.3c01192
日期:2023.6.2
An efficient synthesis of benzo[c]phenanthridine alkaloids via a synergistic combination of C–C bond formation and a cycloaromatization reaction is described. Aryl nitrones react with 7-azabenzonorbornadienes in the presence of a Rh(III) catalyst, providing pharmaceutically useful benzo[c]phenanthridine derivatives in good to moderate yields. Using this methodology, highly useful alkaloids such as
描述了通过 C-C 键形成和环芳构化反应的协同组合有效合成苯并 [ c ] 菲啶生物碱。在 Rh(III) 催化剂存在下,芳基硝酮与 7-氮杂苯并降冰片二烯反应,以良好至中等收率提供药学上有用的苯并 [ c ] 菲啶衍生物。使用这种方法,可以在一个步骤中制备非常有用的生物碱,例如诺法加龙宁、去甲白屈菜红碱、地卡林、去甲血根碱和去甲尼替丁。