Rapid access to C2-quaternary 3-methyleneindolinesviabase-mediated post-Ugi Conia-ene cyclization

Abstract

Highly efficient synthesis of diverse 2,2-disubstituted 3-methyleneindoline derivatives through a one-pot base-promoted post-Ugi 5-exo-dig “Conia-ene” type cyclization has been disclosed. The mechanism study indicates that an intramolecular hydrogen bond may...

Synthesis of Nitrogen-Containing Heterocyclic Scaffolds through Sequential Reactions of Aminoalkynes with Carbonyls

“…Similarly, the three-component reaction of an aminopentanoate, an aldehyde, and an α-isocianoacetamide produced in a one-pot process the 4,5,6,7-tetrahydrofuro [2,3- c ]pyridines by simply heating the solution in toluene in the presence of ammonium chloride. [ 92 ] A base-promoted post-Ugi 5-exo-dig “Conia-ene”-type cyclization efficiently afforded a variety of 2,2-disubstituted 3-methyleneindoline derivatives 93 ( Scheme 78 ) [ 93 ].…”

Visible‐Light Mediated Ugi‐Type Reaction for the Synthesis of 3,3‐Disubstituted Phthalides

“…Moreover, the construction of quaternary carbon-containing phthalide remains marginally reported, possibly owing to its synthetic challenge hindered by its distinct congested nature and conformational restriction. [19] During our continuing effort on the modular and streamlined synthesis of bioactive molecules and the unmet demand for green medicinal chemistry, [20] we reported a visible light-assisted platform for the rapid access of functionalized 3,3-disubstituted phthalides employing three-component reaction under mild conditions. The key findings of this work mainly include: (i) photocatalyst-and additive-free; (ii) the ambient air was used as an oxygen source for aerobic oxidation; (iii) mild reaction conditions; one-pot and atomeconomic; (iv) diversity-oriented access to phthalide and fused privileged scaffolds.…”

Green synthesis for diverse bioactive benzo-fused spiroindolines through DBU-catalysed post-Ugi double cyclization

“…13 Our group recently introduced a DBU-mediated post-Ugi Coniaene cyclization assisted by an intramolecular hydrogen bond (Scheme 1d). 14 However, we acknowledge some key concerns:…”

“…13 Our group recently introduced a DBU-mediated post-Ugi Conia-ene cyclization assisted by an intramolecular hydrogen bond (Scheme 1d). 14 However, we acknowledge some key concerns: (1) can this Conia-ene reaction proceed using a catalytic amount of base? (2) how can the Conia-ene reaction be promoted in the absence of a pyridyl group?…”