Cascade reaction of o-enoyl arylisocyanide and o-hydroxy aromatic aldimine: diastereoselective access to a polycyclic spirobenzoxazine chromeno[4,3-b]pyrrole derivative

Abstract

A series of structurally unusual spirobenzoxazine chromeno[4,3-b]pyrrole derivatives have been efficiently constructed in a single operation from readily available starting materials. This domino transformation forms successively three new rings and...

Visible light-induced radical cyclization of o-alkenyl aromatic isocyanides with thioethers: direct synthesis of 2-thioquinolines

“…Isocyanides are extraordinarily versatile and powerful synthons because of their unique reactivity toward electrophiles, nucleophiles, and radicals. 5 As important members of these families, o -alkenyl aromatic isocyanides have received particular attention and have been employed as valuable precursors for the synthesis of diverse classes of heterocycles by base-promoted tandem cyclization reactions, 6 transition-metal-catalyzed annulations, 7 and radical cyclization reactions. 8,10–13 In addition, visible-light catalysis has recently attracted much attention due to its inherent features of operational simplicity, sustainability and green chemistry.…”

Cobalt nanoparticles supported on microporous nitrogen-doped carbon for an efficient catalytic transfer hydrogenation reaction between nitroarenes and N-heterocycles

“…With this attractive protocol, a considerable variety of electrophiles, including alkanes, alcohols, and amines have been synthesized in good to excellent yields. [10][11][12][13] For instance, Wang's group conducted an asymmetric hydrogen auto-transfer reaction that allows the practical synthesis of α-chiral amines by the alkylation of amines with alcohols. 10 Sabater's group discovered that the transfer hydrogenation strategy usually relies on three steps, (i) dehydrogenation, (ii) intermediate reaction, and (iii) hydrogenation, and is an excellent and well-recognized process from the synthetic, economic, and environmental points of view.…”

“…[10][11][12][13] For instance, Wang's group conducted an asymmetric hydrogen auto-transfer reaction that allows the practical synthesis of α-chiral amines by the alkylation of amines with alcohols. 10 Sabater's group discovered that the transfer hydrogenation strategy usually relies on three steps, (i) dehydrogenation, (ii) intermediate reaction, and (iii) hydrogenation, and is an excellent and well-recognized process from the synthetic, economic, and environmental points of view. 13 In addition, considerable progress has also been made in the development of catalysts for transfer hydrogenation reactions.…”

Sequential [3+2] and [4+4] Annulation of Diynone and o‐Hydroxyaryl Azomethine Ylide: Construction of Dihydropyrrole Fused Eight‐Membered Ring Scaffold

“…[16] To our knowledge, the reaction of o-hydroxy aromatic aldimine and diynone has not been investigated thus far. As a continuation of our interests in heterocycles synthesis, [17] herein we disclosed a new transformation, involvign o-hydroxy aromatic aldimines and diynone, to construct dihydropyrrole fused eight-membered ring scaffold (Scheme 1c).…”

“…As shown in entry 15, 3 a was formed in 85% yield at room temperature which was the optimal entry of the whole screening table. Finally, we found that the product yield was not improved by using other amounts of Cs 2 CO 3 , e. g. 50 mol%, 150 mol% (Table 1, entries [17][18].…”