Substituent-controlled site-selective silylation of 2H-indazoles to access silylated 1H-indazoles and 2H-indazoles under transition metal-free conditions

Abstract

Herein, we report a t-BuONa-promoted method for the site-selective silylation of 2H-indazoles.

Silylation of 2H-indazoles by photoinduced hydrogen atom transfer catalysis

“…Recently, Feng et al reported a t BuONa-promoted selective silylation of indazoles (Scheme 1a). 13 As a part of our ongoing work on the visible-light-mediated C–Si bond formation 9 i and functionalization of indazoles, 9 d , g we herein report a visible-light-mediated, metal-free silylation of 2 H -indazole using 4CzIPN as a photocatalyst and a catalytic amount of triisopropylsilanethiol as the HAT reagent. To the best of our knowledge, this is the first report on the installation of triphenylsilyl functionality in the 2 H -indazole moiety under photocatalysis.…”

Photopromoted Free Radical Silylation of 2-Aryl-2H-indazoles with Silanes

“…In synthetic chemistry, several efficient methods for the synthesis of amino, alkyl, sulfonyl, trifluoromethyl, benzyl, heterocyclyl, and other common groups featuring indazoles have been developed by many groups (Scheme a) . Very recently, Feng/He/Liu reported a silylation reaction of 2 H -indazoles via a Si–B bond activation pathway (Scheme b) . Meanwhile, other valuable approaches for preparing the above derivatives are still being studied.…”