Imination of sulfides and sulfoxides with sulfonylimino-lambda3-bromane under mild, metal-free conditions.
Exposure of sulfides and sulfoxides to trifluoromethanesulfonylimino(aryl)-lambda(3)-bromane in dichloromethane at 0 degrees 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 rho 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-lambda(3)-bromane, which involves the attack of a sulfide from the opposite side to bromine(III).
Ochiai
Masahito
M
Graduate School of Pharmaceutical Sciences, University of Tokushima, 1-78 Shomachi, Tokushima 770-8505, Japan. mochiai@ph.tokushima-u.ac.jp
Naito
Masao
M
Miyamoto
Kazunori
K
Hayashi
Satoko
S
Nakanishi
Waro
W
D007097:Imines / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D013440:Sulfides / Q000737:chemistry*; D013450:Sulfones / Q000138:chemical synthesis / Q000737:chemistry*; D013454:Sulfoxides / Q000737:chemistry*
D007097:Imines; D013440:Sulfides; D013450:Sulfones; D013454:Sulfoxides; C540083:sulfonylimino-lambda3-bromane