Pyrrole synthesis through Cu-catalyzed cascade [3 + 2] spiroannulation/aromatization of oximes with azadienes

Abstract

We have disclosed a new synthetic method for the rapid assembly of poly-substituted pyrroles with readily accessible oximes and azadienes as the starting materials. The present approach generates an array...

Deconstructive Insertion of Oximes into Coumarins: Modular Synthesis of Dihydrobenzofuran-Fused Pyridones

“…Therefore, we envisioned exploring the coumarins as synthons to develop novel deconstructive strategies for the synthesis of value molecules, N-heterocycles in particular. With our continued interest in oxime N–O bond transformations (NOT), we report herein for the first time a Cu-catalyzed deconstructive method via a formal insertion of oxime into the coumarin moiety (Scheme d). The oximes are versatile building blocks, which are easy to prepare, nontoxic, stable to air and moisture, and simple to handle.…”

Synthesis of Fully Substituted 5-(o-Hydroxybenzoyl)imidazoles via Iodine-Promoted Domino Reaction of Aurones with Amidines

“…On the basis of the above experimental results and our precedent works with some related reports, , a plausible reaction mechanism for this iodine-promoted domino reaction to access fully substituted 5-( o -hydroxybenzoyl)­imidazole 3 is proposed in Scheme . At first, an aza-Michael addition occurs between 1 and 2 in the presence of I 2 to give the corresponding adduct existing as a tautomerizing equilibrium mixture of ketone/imine A and enol/enamine B .…”

Substrate-Switched Chemodivergent Pyrazole and Pyrazoline Synthesis: [3 + 2] Cycloaddition/Ring-Opening Rearrangement Reaction of Azadienes with Nitrile Imines

“…However, to the best of our knowledge, all of the reported reactions involving BDAs reported so far are limited to cycloaddition and 1,4-addition reactions except for one example. Wei and co-workers developed the Cu-catalyzed cascade [3 + 2] spiroannulation/aromatization of BDAs with oximes via radical process . Thus, the exploitation of novel and unusual reaction model of BDAs would be highly significant and desirable, which would not only extend the reactivity scope of BDAs but also access nitrogen-containing heterocycles that cannot be obtained by other methods.…”