Imination of Sulfides and Sulfoxides with Sulfonylimino-λ3-Bromane under Mild, Metal-Free Conditions

✍ Scribed by Masahito Ochiai; Masao Naito; Kazunori Miyamoto; Satoko Hayashi; Waro Nakanishi

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 299 KB
• Volume: 16
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.201000759

✦ Synopsis

Abstract

Exposure of sulfides and sulfoxides to trifluoromethanesulfonylimino(aryl)‐λ^3^‐bromane in dichloromethane at 0 °C results in a facile transfer of the sulfonylimino group to sulfur atoms and affords N‐triflylsulfilimines and __‐__sulfoximines in high yields under transition‐metal‐free conditions. Imination of (R)‐methyl p‐tolyl sulfoxide proceeded with predominant retention of configuration at the stereogenic sulfur center. The Hammett plot afforded ρ values of −0.58 for para‐substituted thioanisoles and −0.49 for their equivalent sulfoxides, which suggests a buildup of positive charge on the sulfur atoms of sulfides and sulfoxides in the transition state. Calculations suggest a bimolecular nucleophilic‐substitution mechanism on the negatively charged nitrogen atom of the sulfonylimino‐λ^3^‐bromane, which involves the attack of a sulfide from the opposite side to bromine(III).