Ruthenium(II)-Catalyzed Ortho-C–H Alkylation of Naphthylamines with Diazo Compounds for Synthesis of 2,2-Disubstituted π-Extended 3-Oxindoles in Water

Abstract

Ruthenium­(II)-catalyzed ortho-C–H alkylation of naphthylamines with diazo compounds for the synthesis of 2,2-disubstituted π-extended 3-oxindoles has been developed. The method represents the first example of C–H alkylation via carbenoid insertion in water as a sustainable solvent. The procedure includes an inexpensive ruthenium catalyst as well as aqueous media and results in the release of benign N2. The π-extended 3-oxindole products exhibit favorable antitumor properties and remarkable fluorescent properties in aqueous solution for fluorescent imaging.

Efficient synthesis of ethyl 2-(oxazolin-2-yl)alkanoates via ethoxycarbonylketene-induced electrophilic ring expansion of aziridines

“…Alkyl 2-diazo-3-oxoalkanoates 1 were synthesized by referring our previous procedure [ 22 – 23 ]. Their analytic data are identical to previously reported ones 1a , b [ 23 ], 1c , d [ 24 ], 1e , g [ 25 ], 1f [ 26 ], 1h [ 27 ] and 1i [ 28 ]. Aziridines 2 were prepared according to our previous method [ 21 ] and their analytic data are identical to previously reported ones 2a–f [ 21 ] and 2g [ 29 ].…”

Transition‐Metal‐Catalyzed C−H Bond Functionalization of Arenes/Heteroarenes via Tandem C−H Activation and Subsequent Carbene Migratory Insertion Strategy

“…An efficient synthesis of 2,2-disubstituted π-extended 3oxindoles has recently been developed by Szostak and coworkers in 2020 via a Ru(II)-catalyzed CÀ H activation/ annulation process (Scheme 32e). [94] Substituted naphthylamines and α-diazo-β-ketoesters have been used as the requisite coupling partners with the reaction taking place in aqueous medium and N 2 being the benign by-product. The alkylation/ annulation sequence occurs via a cascade CÀ H alkylation/1,2shift thus producing a spectrum of oxindole scaffolds with promising cytotoxic properties and favourable fluorescence.…”

Efficient synthesis of ethyl 2-(oxazolin-2-yl)alkanoates via ethoxycarbonylketene-induced electrophilic ring expansion of aziridines

“…Alkyl 2-diazo-3-oxoalkanoates 1 were synthesized by referring our previous procedure [22,23]. Their analytic data are identical to previously reported ones 1a,b [23], 1c,d [24], 1e,g [25], 1f [26], 1h [27] and 1i [28]. Aziridines 2 were prepared according to our 12 previous method [21] and their analytic data are identical to previously reported ones 2a-f [21] and 2g [29].…”