NH₄HF₂ as a Selective TBS-Removal Reagent for the Synthesis of Highly Functionalized Spiroketal via Tandem Deprotection/Spiroketalization Procedure

NH₄HF₂ has been used for the first time to selectively remove the TBS protecting groups from diol ketone precursors in the synthesis of highly functionalized spiroketals. This method allows the synthesis of [5,6], [6,6], and [6,7] spiroketal skeletons, as well as benzannulated spiroketal with retention of acid-sensitive groups. In this way, spiroketals can be synthesized with diverse substituent groups in the skeleton or on side chains. To demonstrate the utility of this methodology, the diverse transformations of highly functionalized spiroketal <b>3f</b> were also investigated

Stereoselective Synthesis of <i>Z</i>‑Vinylsilanes via Palladium-Catalyzed Direct Intermolecular Silylation of C(sp²)–H Bonds

An efficient and convenient palladium-catalyzed direct intermolecular silylation of C­(sp²)–H bonds by using disilanes as the silicon source with the assistance of a readily removable bidentate directing group is reported. This strategy provided a regio- and stereoselective protocol for exclusive synthesis of <i>Z</i>-vinylsilanes with reasonable to excellent yields and good functional group compatibility. Silylation of the isolated palladacycle intermediate revealed the <i>Z</i>-stereoselective pathway. Moreover, the practicality and effectiveness of this method were illustrated by a gram-scale experiment and further functionalization of the silylation product

Copper-Catalyzed Selective <i>ortho</i>-C–H/N–H Annulation of Benzamides with Arynes: Synthesis of Phenanthridinone Alkaloids

An efficient and convenient copper-catalyzed method has been developed to achieve direct <i>ortho</i>-C–H/N-H annulation to synthesize phenanthridinones with arynes. This method highlights an emerging strategy to transform inert C–H bonds into versatile functional groups in organic synthesis and provides a new way to synthesize phenanthridinone alkaloids efficiently

Copper-Catalyzed Selective <i>ortho</i>-C–H/N–H Annulation of Benzamides with Arynes: Synthesis of Phenanthridinone Alkaloids

An efficient and convenient copper-catalyzed method has been developed to achieve direct <i>ortho</i>-C–H/N-H annulation to synthesize phenanthridinones with arynes. This method highlights an emerging strategy to transform inert C–H bonds into versatile functional groups in organic synthesis and provides a new way to synthesize phenanthridinone alkaloids efficiently

Copper-Catalyzed Selective <i>ortho</i>-C–H/N–H Annulation of Benzamides with Arynes: Synthesis of Phenanthridinone Alkaloids

An efficient and convenient copper-catalyzed method has been developed to achieve direct <i>ortho</i>-C–H/N-H annulation to synthesize phenanthridinones with arynes. This method highlights an emerging strategy to transform inert C–H bonds into versatile functional groups in organic synthesis and provides a new way to synthesize phenanthridinone alkaloids efficiently