An unprecedented enantioselective synthesis of spiro-g-lactams via a sequential C À H olefination/asymmetric [4+1] spirocyclization under a simple Co II /chiral spiro phosphoric acid (SPA) binary system is reported. A range of biologically important spiro-g-lactams are obtained with high levels of enantioselectivity (up to 98 % ee). The concise, asymmetric synthesis of an aldose reductase inhibitor was successfully achieved. Notably, contrast to previous reports that relied on the use of cyclopentadienyl or its derivatives (achiral Cp*, Cp tBu , or chiral Cp x ) ligated Co III complexes requiring tedious steps to prepare, cheap and commercially available cobalt(II) acetate tetrahydrate was used as an efficient precatalyst. Figure 1. Selected bioactive molecules with spiro-g-lactam scaffolds.

A concise and direct synthetic strategy for the construction of 2-aryliminochromene skeleton by cascade three-component coupling reaction of arynes, N,S-keteneacetals, and DMF in good yields has been disclosed. The process demonstrates the first example of aryne chemistry combined with N,S-keteneacetals. Using this strategy, an expeditious synthesis of biologically important arylimino-2H-chromene-3- carboxamides was achieved.

An efficient synthesis of thiazolidine-2,4,5-triimine derivatives was developed via Ni-catalyzed oxidative double isocyanide insertion to thioureas under air conditions, in which thioureas play three roles as a substrate, a ligand, and overcoming isocyanide polymerization. The reaction is featured by employing a low-cost and low loading Ni­(acac)2 catalyst, without any additives, and high atom economy. This is the first example to directly apply a Ni­(II) catalyst in oxidative double isocyanide insertion reactions.

A new CuI/1,10-phen-catalyzed reaction for the synthesis of 3-ylideneoxindoles from readily available isatins and ethyl isocyanoacetate, in which ethyl isocyanoacetate acts as a latent two-carbon donor like the Wittig reagent, is reported. A tandem procedure including 1,3-dipolar cycloaddition/inverse 1,3-dipolar ring opening/olefination allows the preparation of 3-ylideneoxindoles with broad functional group tolerance.

Nickel(II) can be used to catalyze the hetero [2+2+1] cycloaddition of 2‐alkynylaryl isothiocyanates and isonitriles in 2‐methyltetrahydrofuran (2‐MeTHF) to give a wide array of thieno[2,3‐b]indoles in excellent yields. The reaction is featured by employing as little as 0.3 mol% nickel(II) acetylacetonate [Ni(acac)2] under air conditions in the absence of any additives (additional reducing agents and external ligands). This is the first successful example to apply nickel(II) directly in hetero [2+2+1] cycloadditions.magnified image