Zn(OAc)₂-Catalyzed C3-Carbonylacetylation of Indoles with α-Diazoketones Involving Wolff Rearrangement

Abstract

Zn­(OAc)2-catalyzed highly regioselective carbonylacetylation of indoles and pyrroles with α-diazoketones has been developed. This transformation involves a combination of Wolff rearrangement/cross-coupling relay and provides an efficient approach to versatile 3-carbonylacetylindoles and 2-carbonylacetylpyrroles with a broad range of functional group tolerance.

Copper-Catalyzed Annulation of Indolyl α-Diazocarbonyl Compounds Leads to Structurally Rearranged Carbazoles

“…In addition to the formation of naphthalene products, a third carbazole isomer (e.g., 16 ) was also identified in the complex byproduct mixtures of several annulation reactions. Analytically pure 16 was isolated upon prolonged heating of 11a with scandium­(III) triflate open to air (Scheme B) and represents a carbazole that likely arises via a Wolff type rearrangement similar to that reported by Taylor and Unsworth . While this isomer is only formed in small quantities (if at all) under the copper-catalyzed annulations conditions, its presence as a major carbazole isomer under scandium catalysis is interesting as there may be the potential to design reaction conditions that are selective for the formation of this isomer.…”

Rhodium-Catalyzed C═N Bond Formation through a Rebound Hydrolysis Mechanism and Application in β-Lactam Synthesis

“…We found that Rh 2 (esp) 2 cannot achieve the Staudinger cyclization; thus, Rh 2 (OAc) 4 (1 mol %) was used and delivered lactam 5a in 83% yield with excellent diastereoselectivity (>20:1 dr) (Scheme ). The reaction involves the rhodium-catalyzed imine formation and Wolff rearrangement to afford imine and ketene intermediates, respectively. Then, the thermal Staudinger cyclization of imine with ketene occurs to form lactam 5a .…”

Cascade Wolff Rearrangement and Double N‐Acylation: A Cyclization of α‐Diazoketones with 2‐aminopyridines or 3‐aminopyrazoles to Synthesize Fused Pyrimidinediones

“…The solvents were also investigated, such as toluene, DMF, DMSO, 1,4dioxane, H 2 O, acetonitrile, dimethyl carbonate and diethyl carbonate. The yield could be improved when diethyl carbonate was used as the solvent (Table 1, entries [8][9][10][11][12][13][14]. The effect of temperature on the method was also tested.…”