Stereoselective control of planar alpha-dimethylsulfonium benzyl carbanions. Synthesis of optically pure trans-aziridines.
(R)-N-sulfinylimine and (S)-N-sulfinylimine react with the ylide derived from (S)-dimethyl-[2-(p-toluenesulfinyl)phenyl]sulfonium salt, affording trans-2,3-disubstituted aziridines. A complete trans selectivity in low facial diastereoselectivity is observed when the configuration at the sulfur atoms of the reagents is the same. Otherwise, when their configurations are different, the reaction evolved with total facial diastereoselectivity and the cis/trans ratio ranged between 1/4.2 and 1/9. Theoretical calculations indicate the reaction proceeds mainly by evolution of a planar free carbanion. The relative stability of the transition states predicts a trans/cis ratio that is in excellent agreement with the experimental results.
Departamento de Quimica Organica (ETSII), Universidad de Valladolid, Po del Cauce s/n, 47011 Valladolid, Spain.
Yolanda
Y
Arroyo
Angela
A
Meana
J Félix
JF
Rodríguez
M Ascensión
MA
Sanz-Tejedor
Inés
I
Alonso
José L
JL
García Ruano
D000838:Anions; D001388:Aziridines / Q000138:chemical synthesis*; D007097:Imines / Q000737:chemistry; D013237:Stereoisomerism
D000838:Anions; D001388:Aziridines; D007097:Imines