Catalytic Synthesis of 1-Benzoxazolo[3,2-]pyridin-1-ones via Formal [3 + 3] Annulations of NHC-Generated Alkynyl Acylazoliums with Benzoxazolyl Acetates and Their Photophysical Studies.

We disclose the synthesis of a tricyclic fused N-heterocycle via the NHC-catalyzed annulation of either a ynal or an alkynyl ester with readily accessible benzoxazolyl acetate. While the annulation with ynals requires an oxidant, the reaction with alkynyl esters proceeds via the direct generation of alkynyl acylazolium intermediates with an NHC. With the dearth of catalytic processes to access these 1-benzoxazolo[3,2-]pyridin-1-ones from simple starting materials, this method is especially important.

Electrochemical Regioselective C()-H Selenylation and Sulfenylation of Substituted 2-Amino-1,4-naphthoquinones.

A straightforward and efficient electrochemical method for regioselective C()-H selenylation and sulfenylation of substituted 2-amino-1,4-naphthoquinones has been unearthed. This oxidative -coupling reaction avoids using transition metal catalysts, oxidants, and high temperatures. The other notable advantages of this protocol are the tolerance of diverse functional groups, mild reaction conditions at ambient temperature, energy efficiency, good to excellent yields, short reaction times (in minutes), gram-scale applicability, and eco-friendliness.