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The effective and mild [4+1] annulation of ninhydrin-derived MBH carbonates with α,β-unsaturated ketones has been developed, providing a wide range of multisubstituted furans in high yields (up to 90%) with excellent β-regioselectivities. In contrast, the polysubstituted cyclopentenes bearing dispiro-bisindanedione motifs were obtained via classical [3+2] annulations by employing ninhydrin-derived MBH carbonates with 2-arylidene-1,3-indandiones under the same catalytic conditions. Furthermore, the structures of two kinds of cycloadducts were straightforwardly confirmed through X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

A cobalt-catalyzed esterification-peroxidation was realized by a Co(II)/TBHP system to deliver α-acyloxy esters from readily available starting materials in moderate to good yields. In this process, the O–H insertion reaction of diazo reagents, C–H activation and peroxidation were fused into a reaction system. Preliminary mechanistic studies show that a free-radical process is involved in this method. [ABSTRACT FROM AUTHOR]

A simple and green procedure was established by [3 + 3] cycloaddition reaction of isatin derived cyclic imine 1,3-dipoles with α,β-unsaturated aldehydes, giving the desired spiro heterocyclic oxindoles with aza-quaternary centers in good yields and diastereoselectivities. It should be noted that water can be employed as a suitable solvent for the improvement of diastereoselectivity., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)