Polycyclic Ring Formation Using Bis-diazolactams for Cascade Stitching Sara A. Bonderoff Albert Padwa 10.1021/acs.joc.6b02663.s002 https://acs.figshare.com/articles/dataset/Polycyclic_Ring_Formation_Using_Bis-diazolactams_for_Cascade_Stitching/4498481 The chemoselective reaction of donor/acceptor (D/A) and acceptor/acceptor (A/A) diazo moieties in the same molecule was examined using 3-diazo-1-(ethyl 2-diazomalonyl)­indolin-2-one under rhodium­(II) catalysis. The metallo carbenoid derived from the D/A diazo group is preferentially formed and undergoes selective CH, NH, and OH insertion reactions, cyclopropanation, cyclopropenation, sulfur ylide formation/2,3-sigmatropic rearrangement, as well as nitrogen ylide formation followed by azetidine ring expansion. The initial reaction can be paired with a subsequent tandem cascade sequence involving dipole formation/cycloaddition in either an intra- or intermolecular sense to generate polycyclic <i>N</i>-heterocycles in one pot, with the formation up to three new rings in a single operation. Excellent diastereoselectivity was observed in the intramolecular cycloaddition reaction producing 5 to 7-membered rings. 2016-12-15 00:00:00 chemoselective reaction intramolecular cycloaddition reaction NH Cascade Stitching Excellent diastereoselectivity CH tandem cascade sequence Polycyclic Ring Formation metallo carbenoid diazo OH insertion reactions polycyclic N 7- membered rings azetidine ring expansion nitrogen ylide formation