Abstract
A simple, convenient, and regioselective 1,3-dipolar cycloaddition of 9-diazo-9H-fluorene or diphenyldiazomethane to 2-arylidene-1H-indene-1,3(2H)-diones afforded a series of novel dispiro[indane-2,3'-pyrazole-5',9 ''-fluorene] and spiro[indene-2,3'-pyrazole] derivatives in moderate to excellent yields. Chemical structures of all products have been fully established by D-1 (H-1, C-13, C-13-DEPT 90) and 2D homonuclear and heteronuclear correlation NMR spectrometry experiments (H-1-H-1-DQF-COSY, H-1-H-1-TOCSY, C-13-H-1-HSQC, C-13-H-1-HMBC, H-1-H-1 ROESY, and HSQC-TOCSY) and regioselectivity of the reported procedure has been demonstrated in all products. DFT reactivity indices of these cycloaddition reactions have been studied. 1,3-Dipolar cycloaddition of 9-diazo-9H-fluorene and diphenyldiazomethane to 2-arylidene-1H-indene-1,3(2H)-diones as dipolarophiles are reactions governed by a concerted mechanism exhibiting high regioselectivity.
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