Synthesis of 6‐Aryl‐5‐iodobenzo[e]pyrido[1,2‐a]indoles by 6‐endo‐dig Iodocyclization

Abstract

Regioselective access to 6-aryl-5-iodobenzo[e]pyrido[1,2-a]indoles was realized by using af acile 6-endo-dig iodine-mediated cyclization under mild reaction conditions. Further functionalization of the resulting products by using Pd-catalyzed coupling reactions was demonstrated, leading to the tetracyclic core substitutedw ith two distinct functional groupsinaregioselective fashion.Scheme1.Synthetic approaches to benzo[e]pyrido[1,2-a]indoles.

Symmetry-based approach to oligostilbenoids: Rapid entry to viniferifuran, shoreaphenol, malibatol A, and diptoindonesin G

“…To this end, 11 was first transformed to aldehyde 13 via 12 through a two-step sequence consisting of deacetylation and Dess–Martin oxidation [39]. To our delight, the subsequent Suzuki cross-coupling of 13 with 3,5-dimethoxyphenylboronic acid under the reaction conditions analogous as described before [26] proceeded well and furnished 14 in 88% yield. This intermediate was used for our previous syntheses of permethylated analogues of viniferifuran, malibatiol A, and shoreaphenol [13].…”

“…As shown in Scheme 1, our idea stemmed from recognition of the symmetry element [19] of the target molecules. We expected that the key intermediate (inset box of Scheme 1) could be constructed from the monoiodo compounds 1 , 2 , or 3 through a sequence involving Sonogashira coupling, iodocyclization [20–26], and Suzuki coupling. As the starting materials ( 1 , 2 , and 3 ) were readily available from the corresponding C 2 symmetric precursors via monoiodination, we decided to evaluate this route.…”

Recent advances in the synthesis of indolizines and their π-expanded analogues

“…87 Some derivatives were applied in Sonogashira or Suzuki coupling, and thus diversity of products was maximized by introducing two different substituents at the positions C5 and C6. 87 Some derivatives were applied in Sonogashira or Suzuki coupling, and thus diversity of products was maximized by introducing two different substituents at the positions C5 and C6.…”

The Kröhnke synthesis of benzo[a]indolizines revisited: towards small, red light emitters

“…There are a few basic classes of benzoindolizines: pyrrolo[1,2- a ]quinolines, 25–36 pyrrolo[2,1- a ]isoquinoline, 37–40 benzo[ b ]indolizine 41–48 and benzo[ a ]indolizines (pyrido[2,1- a ]isoindoles) 49–61 (Fig. 1).…”