14142-03-1Relevant academic research and scientific papers
Heterocycle Formation through Aza-Annulation: Stereochemically Controlled Syntheses of (+/-)-5-Epitashiromine and (+/-)-Tashiromine
Paulvannan, K.,Stille, John R.
, p. 1613 - 1620 (1994)
N-alkenylamines, stabilized through conjugation with an electron-withdrawing group, undergo aza-annulation with acryloyl chloride to provide a convergent route for the construction of six-membered nitrogen heterocycles.In addition to enhancing the C-alkylation process of annulation relative to the competing N-acylation process, the electron withdrawing substituent controlled the regioselectivity of alkene formation in both the intermediate enamine and in the unsaturated lactam product.A variety of functional groups, which include -COMe, -COPh, -CO2R, -CONHPh, -CN, -P(O)(OEt)2, and -SO2Ph, were used to determine the effect of the electron-withdrawing substituents upon both the annulation reaction with acryloyl chloride and the subsequent hydrogenation process.When the enamide annulation product was stabilized through conjugation with ester or amide substituents, catalytic hydrogenation of the aza-annulation product resulted in the formation of vicinal stereocenters with high cis selectivity.The utility of this methodology was demonstrated by application of the condensation/aza-annulation/hydrogenation sequence as the key for construction and stereochemical control of the indolizidine ring system of (+/-)-tashiromine.
Facile Synthesis of Spirocyclic Lactams via [3+2] and [3+3] Aza-Annulation Reactions
Hayrapetyan, Davit,Stepanova, Valeriya
supporting information, p. 2121 - 2125 (2021/07/26)
Spirocyclic pyrrolidones and piperidones were synthesized starting from readily available α-ketolactones and α-ketolactams employing [3+2]- and [3+3]-aza-annulation reactions. Annulation reactions proceeded with good yields and further reduction of the ex
Visible Light Promoted β-C—H Alkylation of β-Ketocarbonyls via a β-Enaminyl Radical Intermediate
Wang, Dehong,Zhang, Long,Luo, Sanzhong
, p. 311 - 320 (2018/02/21)
A 5πe carbonyl activation mode is reported on the basis of photo-induced single-electron-transfer (SET) oxidation of a secondary enamine. The resultant β-enaminyl radical intermediate was trapped by a wide range of Michael acceptors, producing β-alkylation products of β-ketocarbonyls in a highly efficient manner.
