Rhodium-Mediated Dipolar Cycloaddition of Diazoquinolinediones

Abstract

As an entry to furoquinoline structures of natural origin, the rhodium-mediated dipolar cycloaddition of diazoquinolinediones with alkenes and alkynes has been examined. Because of the unsymmetrical nature of the diazo compounds, both linear and angular furoquinoline products are possible. For the most part, a mixture of regioisomers is generated in moderate to good yields, though in a few cases dominant products are obtained in high yields. The products can be further converted to naturally occurring alkaloids such as isodictamnine. A novel observation in this work is that catalytic quantities of acid enhance the yield and regiochemical control in the cycloaddition.

Selectivity in cyclopropanations and 1,3-cycloadditions in transition metal-catalyzed decompositions of 2-diazocyclohexane-1,3-diones and the corresponding phenyliodonium ylides

“…This is surprising in the case of 6a, because the corresponding diazo derivative 6a adds normally to olefins. 18 The diazo analogue 7a of ylide 7b is not known in the literature; and attempts towards its preparation were not successful. In the case of 8a,b both the diazo derivative and the ylide are too stable and may not be decomposed under normal conditions.…”

One Pot Multicomponent Synthesis of Anti-inflammatory Active Tetrahydrofuro[3,2-c]pyridinone-2-carboxylate Derivatives

“…Most of them may suffer from tedious steps, low yields and poor region and stereoselectivity [9][10][11][12][13][14][15][16][17]. Recently we have developed two new methodologies for the synthesis of C3-dihydrofuran substituted coumarins, dihydrofuro pyrazole by employing one pot multicomponent synthesis with pyridinium ylide.…”

Synthesis of Tricyclic Quinolones and Naphthyridones by Intramolecular Heck Cyclization of Functionalized Electron‐Rich Heterocycles

“…[14] A few general, although not simple, approaches to tricyclic pyrrolo-, furo-, and thienoquinolines have been described in the literature. Photochemical [10a,10b,15] and radical [16] cyclizations of amide systems have been reported to give poor yields of thieno-and pyrrolo [2,3-c]quinolines, while the cycloaddition of 4-hydroxy-2-quinolones [17] and diazoquinolinediones [18] gives furoquinolines. Pyrolysis of azidoquinoline derivatives [19] and the traditional PaalKnorr reaction [20] give pyrroloquinolines, while pyrolysis of azidobenzylthiophene derivatives gives thienoquinolines.…”