Direct construction of benzimidazo[l,2-c]quinazolin-6-onesviametal-free oxidative C–C bond cleavage

Abstract

A highly regioselective protocol has been developed for the synthesis of benzimidazo[l,2-c]quinazolin-6-ones via C–C bond cleavage and triple C–N bond formation.

Copper-Catalyzed Annulation or Homocoupling of Sulfoxonium Ylides: Synthesis of 2,3-Diaroylquinolines or α,α,β-Tricarbonyl Sulfoxonium Ylides

“…As part of our ongoing interest in the synthesis of heterocycles, , we report our findings on copper-catalyzed synthesis of 2,3-diaroylquinolines through [4+1+1] annulation of sulfoxonium ylides and anthranils (Scheme c, right) . Moreover, an efficient protocol for the synthesis of α,α,β-tricarbonyl sulfoxonium ylides is also presented (Scheme c, left).…”

Research Progress on C2—C3 Bond Cleavage of Indole and Its Derivatives

“…2018 年, 华中师范大学吴安心和武汉工程大学贾 丰成团队 [30] 以靛红和炔酯为底物, 发展了一例 TBHP/无 机碱协同促进合成 4-喹诺酮的绿色新方法. 该反应首先 也是靛红在 TBHP 的氧化下产生靛红酸酐, 随后在 2018 年, 江南大学邹亮华课题组 [31] 报道了仅在氧 气气氛条件下实现了靛红的 C2-C3 键氧化切断及与邻 苯二胺间的串联环化反应. 该反应的机理如下: 首先靛 红在氧气条件下发生 Baeyer-Villiger 氧化转化为靛红酸 酐, 随后其邻近苯环的羰基与邻苯二胺一个氨基缩合脱 水得到亚胺 25C, 与前述例子很大的区别是没有发生脱 除 CO 2 得到酰胺, 随后氨基进一步对另外一个羰基进 攻, 再发生分子内的重排和缩合脱水就得到目标产物 67a (Scheme 26).…”

Copper‐Catalyzed Aerobic Oxidative Ring Expansion of Isatins: A Facile Entry to Isoquinolino‐Fused Quinazolinones

“…[ 7 ] For example, Zou and co‐workers reported an efficient and practical method for the construction of benzimidazo[l,2‐ c ]quinazolin‐6‐ ones through the cleavage of the C2—C3 bond and insertion of heteroatoms using molecular oxygen as the oxidant. [ 7a ] And interestingly, Bathini described an efficient regioselective ring expansion reaction of isatins with aldehydes for the synthesis of α ‐aryl/heteroaryldiazomethane through the insertion of aldehydic carbonyl into the C3—C4 bond. [ 7c ]…”

“…[ 7a ] And interestingly, Bathini described an efficient regioselective ring expansion reaction of isatins with aldehydes for the synthesis of α ‐aryl/heteroaryldiazomethane through the insertion of aldehydic carbonyl into the C3—C4 bond. [ 7c ]…”

“…Common methods for the ring‐expansion reaction of isatins and their derivatives are as follows: 1) ring‐expansion through the cleavage of the C2—N1 bond with enamines to synthesize multisubstituted quinoline‐4‐carboxamides derivatives; [ 6 ] 2) ring‐formation through the insertion of atoms into the C2—C3 or C3—C4 bond. [ 7 ] For example, Zou and co‐workers reported an efficient and practical method for the construction of benzimidazo[l,2‐ c ]quinazolin‐6‐ ones through the cleavage of the C2—C3 bond and insertion of heteroatoms using molecular oxygen as the oxidant. [ 7a ] And interestingly, Bathini described an efficient regioselective ring expansion reaction of isatins with aldehydes for the synthesis of α ‐aryl/heteroaryldiazomethane through the insertion of aldehydic carbonyl into the C3—C4 bond.…”