5‐Ammonium‐4,4‐dimethylvaleryl (Amv) Group: Generation from Acryloyl Group through Decatungstate‐Catalyzed C(sp³)−H Addition and Removal by Base‐Triggered Cyclization

Abstract

The 5‐ammonium‐4,4‐dimethylvaleryl (Amv) group was generated by conversion of acryloyl group through decatungstate‐catalyzed addition of C(sp3)−H bond of i‐BuNH2⋅HCl under the irradiation of UV light (365 nm or 405 nm). Treatment of Amv‐protected alcohols and anilines with aqueous Na2CO3 promoted the efficient deprotection of Amv. This is a unique method for the efficient removal of acryloyl groups from phenols, alcohols, and anilines. The selective removal of acryloyl groups through Amv in the presence of another acetyl or benzoyl group was demonstrated. The base‐triggered intramolecular cyclization of Amv was monitored by the release of a fluorescent molecule, and it was found that cyclization by Na2CO3 was very rapid (within 1 min) and that some weak bases such as 2,6‐lutidine are sufficient to promote cyclization.

Boronyl-Group-Assisted Decatungstate-Catalyzed Benzylic C(sp3)–H Alkylation

“…We recently developed the C­(sp 3 )–H alkylation of ammonium salts using the decatungstate photocatalyst, [W 10 O 32 ] 4– (Scheme A). − In these reactions, electrostatic interactions between the cationic ammonium group (−NH 3 + ) and the anionic [W 10 O 32 ] 4– play a key role. We envisioned that electron-rich [W 10 O 32 ] 4– could function as a hydrogen bond acceptor and interact with a boronyl group, which could function as a hydrogen bond donor.…”