Synthesis and Anticancer Evaluation of 2,3-Disubstituted Indoles Derived from Azobenzenes and Internal Olefins: EJOC 2017

Synthesis and Anticancer Evaluation of 2,3-Disubstituted Indoles Derived from Azobenzenes and Internal Olefins
Azo-directed rhodium(III)-catalysed C–H functionalization and intramolecular annulation reactions between azobenzenes and internal olefins are described. This transformation leads to 2,3-disubstituted free (NH)-indoles with excellent site-selectivity and functional-group compatibility. The resulting indoles were evaluated for in-vitro anticancer activity against human endometrial adenocarcinoma cells (Ishikawa), triple negative human breast cancer cells (MDA-MB-231), and human renal cancer cells (Caki-1). 2,3-Disubstituted indoles 3b, 3k, and 5b were found to show potent cytotoxic effects that were competitive with the anticancer agent doxorubicin.

Cyclopropane Intermediates from Insertion Reactions of Platinum–Carbenes: A Route to Heterospiranes: Synlett 2017

Cyclopropane Intermediates from Insertion Reactions of Platinum–Carbenes: A Route to Heterospiranes

Heteroaromatic-anchored enynals with a pendent alkene group were successfully cyclized through a Huisgen-type [3+2] cycloaddition to give a tetracyclic Pt–carbene complex that underwent insertion into the C–H bond in the β-position to give fused cyclopropanes that are otherwise inaccessible. On heating, the cyclopropanes smoothly rearranged to form the corresponding heterospiranes with excellent levels of stereoselectivity and high yields.

Intramolecular Keto Lactam Condensation: A Convenient and Straightforward Approach to Bicyclic Vinylogous Lactams: EJOC 2017

Intramolecular Keto Lactam Condensation: A Convenient and Straightforward Approach to Bicyclic Vinylogous Lactams

Although the aldol condensation is a well-known reaction, the aza-type aldol condensation, namely, the intramolecular condensation of common keto lactams leading to bicyclic vinylogous lactams, is a highly demanding transformation, with potential applications in both organic synthesis and medicinal chemistry. The known methods for this type of cyclization require several steps. In this paper, we disclose a straightforward approach that consists of the in-situ formation of silyl enol ethers with tert-butyldimethylsilyl trifluoromethanesulfonate (TBDMSOTf), lactam activation with triflic anhydride (Tf2O), and a tandem cyclocondensation reaction. The reaction can be run in a one-pot manner or in a two-step fashion, both under mild conditions. The yields for the one-pot version were 52–80 %. In some cases, the two-step version gave higher overall yields (44–85 %) than the one-pot version.