Cu-catalyzed [1,3]-asymmetric methoxy rearrangement of N-methoxyanilines: mechanistic insight Kazuki Masukawa, Amu Kojima, Takuma Sato, Masahiro Terada, Itaru Nakamura Catalysis Science and Technology, 2025 A cationic Cu catalyst ligated to a chiral NHC ligand, which has an (ortho-carbamoyl)phenyl group on the nitrogen atom of (S,S)-diphenylimidazolidinylidene, efficiently promoted the asymmetric [1,3]-methoxy rearrangement of N-methoxyanilines.
Ag-Catalyzed Cyclization-Intermolecular Sulfinyl Group Transfer Cascade Reactions Enabling Enantioselective Synthesis of 4-Sulfinylisoquinolines Itaru Nakamura., Keiryo Kubota, Hiroki Tashiro, Yushiro Saito, Masahiro Terada Chemistry A European Journal, 2025 N‐Sulfinylimines derived from ortho‐alkynylbenzaldehydes were efficiently converted into the corresponding 4‐sulfinylisoquinolines in good to excellent yields. The reaction proceeds via cyclization followed by intermolecular migration of the sulfinyl group from the nitrogen atom to the silver‐bound carbon of the resulting cyclized vinylsilver intermediate with the aid of either a counteranion or a nucleophilic species. Moreover, the Ag‐catalyzed reaction in the presence of quinidine acetate as a chiral nucleophilic cocatalyst yielded chiral isoquinolines with high enantioselectivities through a dynamic kinetic asymmetric transformation (DYKAT).
Divergent Synthesis of Anisidines by Controlling Cu-Catalyzed [1,3]-Methoxy Rearrangement Itaru Nakamura, Riku Konta, Yasuhiro Ishida, Mai Tachibana, Masahiro Terada Advanced Synthesis and Catalysis, 2023 A divergent synthesis of ortho‐anisidines was achieved by controlling Cu‐catalyzed [1,3]‐methoxy rearrangement. The reactions of N‐alkoxyanilines having an electron‐donating group (EDG), such as an alkyl or anisyl group, at the ortho position and a pivaloyl group on the nitrogen atom in the presence of catalytic amounts of IPrMeCuCl and AgNTf2 afforded the corresponding 6‐substituted 2‐anisidines with good product selectivity through a [1,3]‐rearrangement of the methoxy group to the unsubstituted ortho position. In contrast, the reactions of N‐ methoxyanilines having a benzyloxycarbonyl group on the nitrogen atom using IPrCuBr and AgBF4 as catalysts afforded 3‐substituted 2‐anisidines via a domino process involving a [1,3]‐rearrangement of the methoxy group to the EDG‐substituted ortho position followed by a [1,2]‐rearrangement of the EDG of the resulting ortho‐quinol imine intermediate.
Silver-Catalyzed para-Selective Sulfenyl Group Transfer Reactions of N-Sulfenylanilides Itaru Nakamura, Ichiro Muranushi, Takato Asoh, Masahiro Terada Chemistry A European Journal, 2023 Silver‐catalyzed reactions of N‐sulfenylanilides afforded the corresponding p‐sulfenylanilides in good to high yields with good para selectivity. The transformation has a high compatibility of functional groups, such as ester, bromo, and iodo groups. Mechanistic studies indicate that the rearrangement reaction proceeds through intermolecular transfer of the sulfenyl group.
Synthesis of Curved Polycyclic Arenes Embedded with Oxepine and Thiepine Using Ring Expansion Strategy Sheng Zhang, Hidenori Matsuyama, Itaru Nakamura, Masahiro Terada, Tienan Jin Organic Letters, 2023 A tandem oxidative ring expansion of a six- to seven-membered ring was developed to construct a new class of negatively curved polycyclic arenes embedded with oxepine and thiepine, namely, dibenzo[b,f]phenanthro[9,10-d]oxepine (DBPO) and dibenzo[b,f]phenanthro[9,10-d]thiepine (DBPT), respectively. Mechanistic studies disclosed that an unexpected [4 + 2] cycloadduct formed between the alkene moiety of o-biphenyl-linked methylenexanthenes and o-chloranil serves as a radical cation or a dication equivalent that facilitates the FeCl3-mediated tandem ring expansion process.
Synthesis of meta-Aminophenol Derivatives via Cu-Catalyzed [1,3]-Rearrangement—Oxa-Michael Addition Cascade Reactions Itaru Nakamura, Mai Tachibana, Riku Konta, Hiroki Tashiro, Masahiro Terada Molecules, 2023 Cu-catalyzed reactions of N-alkoxy-2-methylanilines and alcohols in the presence of catalytic amounts of IPrCuBr and AgSbF6 afforded the corresponding meta-aminophenol derivatives in good to high yields. These reactions proceed via a [1,3]-rearrangement, in which the alkoxy group migrates from the nitrogen atom to the methyl-substituted ortho position, followed by an oxa-Michael reaction of the resulting ortho-quinol imine intermediate.
