Synthesis of Fluoren-9-ones by the Palladium-Catalyzed Cyclocarbonylation of o-Halobiaryls

Abstract

The synthesis of various substituted fluoren-9-ones has been accomplished by the palladium-catalyzed cyclocarbonylation of o-halobiaryls. The cyclocarbonylation of 4'-substituted 2-iodobiphenyls produces very high yields of 2-substituted fluoren-9-ones bearing either electron-donating or electron-withdrawing substituents. 3'-Substituted 2-iodobiphenyls afford 3-substituted fluoren-9-ones in excellent yields with good regioselectivity. This chemistry has been successfully extended to polycyclic fluorenones and fluorenones containing fused isoquinoline, indole, pyrrole, thiophene, benzothiophene, and benzofuran rings.

Efficient Synthesis of Fluoren-9-ones by the Palladium-Catalyzed Annulation of Arynes by 2-Haloarenecarboxaldehydes

“…1-Methoxyfluoren-9-one ( 36 ) was the major product as determined by comparison of its 1 H and 13 C NMR spectra with those of the known compound. 17 The preference for regioisomer 36 over the other regioisomer can be attributed to coordination of the methoxy group to the palladium in the biarylpalladium intermediate 37 (Figure 2.). 18 This regiochemistry also places the palladium on the inductively more thermodynamically stable carbanionic carbon.…”

Cobalt‐Catalyzed Annulation of Salicylaldehydes and Alkynes to Form Chromones and 4‐Chromanones

“…Thus,t he iodochromone intermediate 6 is amenable to as eries of Pd-catalyzed CÀC coupling reactions including Sonogashira coupling,c yclo-carbonylation, [17] and annulation with benzyne, [18] thus affording the corresponding products 7-9,r espectively,i ng ood yields. Product 3aa can be converted into various chromone-containing derivatives by facile iododesilylation with ICl (Scheme 6).…”

Synthesis and Some Biological Properties of Pyrrolo[1,2‐a]indoles

“…Palladium catalysts are widely used for synthesis of 9 Н ‐pyrrolo[1,2‐a]indol‐9‐ones. For the interaction of 1‐(2‐iodophenyl)‐1 Н ‐pyrrole 224 and 1‐(2‐bromophenyl)‐1 Н ‐pyrrole , the authors used a palladium complex produced from Pd(OAc) 2 , ligand ( p ‐ClC 6 H 4 ) 3 P, and base CsPiv. The reaction of 1‐(2‐carboxyphenyl)‐1 Н ‐pyrrole leading to 9 Н ‐pyrrolo[1,2‐ a ]indol‐9‐one 225 was catalyzed by bis(trichloromethyl) carbonate or phosphorus pentachloride with tin(IV)chloride .…”