AgOTf-catalyzed sequential synthesis of 4-isoquinolones via oxidative ring opening of aziridines and aza-Michael addition

Abstract

An efficient AgOTf-catalyzed sequential reaction involving the oxidative ring-opening of aziridines by DMSO and aza-Michael addition has been developed. A series of 2,3-dihydro-4(1H)-isoquinolones were afforded in moderate to good yields by the formation of one new C[double bond, length as m-dash]O bond and one new C-N bond. The features of this sequential reaction include high bonding efficiency, use of a catalytic amount of catalysts, a broad substrate scope and mild conditions. This methodology provides a good choice for constructing the libraries of 2,3-dihydro-4(1H)-isoquinolones.

[3 + 3]-Cycloaddition of α-Diazocarbonyl Compounds and N-Tosylaziridines: Synthesis of Polysubstituted 2H-1,4-Oxazines through Synergetic Catalysis of AgOTf/Cu(OAc)2

“…It has been widely reported that N -tosylaziridines can undergo nucleophilic ring opening aided by Lewis acid . AgOTf, one of the most commonly used Lewis acid catalysts, was used for this 2 H -1,4-oxazine formation reaction. By analyzing the reaction mixture, the desired product 3a was detected in an isolated yield of 43% (Table , entry 1).…”

Rh2(II)-Catalyzed Intermolecular N-Aryl Aziridination of Olefins Using Nonactivated N Atom Precursors

“…In the absence of a nucleophile and Lewis acid, oxidative ring-opening of aziridine 17a was observed to provide α-amino ethyl ketone 25 in 88% . While this reaction is well established for activated aziridines, , it has not been reported for nonactivated aziridines. Carbon–carbon bonds could also be constructed diastereoselectively by using indole as a nucleophile to produce 26 in 81% yield.…”

Construction of 4‐Isochromanones through Cu(OTf)2‐Catalysed Sequential C=O and C–O Bond Formation

“…Epoxide 2a was prepared by a three‐step sequence starting from commercially sourced 2‐bromobenzaldehyde (Scheme ). 2‐Bromobenzaldehyde underwent a Stille coupling reaction[15a] and a Knoevenagel reaction[15a] to give the desired alkene 1a . Then, selective epoxidation of alkene 1a gave the required epoxide 2a (Scheme ).…”

“…However, few tandem reactions that simultaneously involve the ring opening of epoxides and the Michael addition of electron‐deficient alkenes have been reported. As a part of our ongoing research into the development of highly selective strategies for the synthesis of heterocyclic compounds with complicated structures, we designed and synthesized a new type of substrates containing both an epoxide and an electron‐deficient alkene. When we treated these compounds with DMSO in the presence of a Lewis acid, sequential oxidative ring opening of the epoxide and oxa‐Michael addition took place to give a series of 4‐isochromanones in moderate to good yields through the formation of one C=O bond and one C–O bond (Scheme ).…”