A new entry to enantiopure polysubstituted cyclopropanes: stereoselective denitrogenation of sulfinylpyrazolines under Yb(OTf)3 catalysis.
[Structure: see text] Chemoselective and completely stereoselective denitrogenation of optically pure pyrazolines, derived from 3-sulfinylfuran-2(5H)-ones, into cyclopropanes can be achieved under substoichiometric Yb(OTf)3 catalysis. Reactions evolve in almost quantitative yields with complete retention of the configuration at both carbons flanking the nitrogen atoms. The resulting enantiomerically pure polysubstituted cyclopropanes, containing up to five substituens, can be desulfinylated with Ra-Ni providing polysubstituted cyclopropanecarboxylic acid derivatives.
García Ruano
José L
JL
Departamento de Química Organica, Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain. joseluis.garcia.ruano@uam.es
Peromingo
M Teresa
MT
Martín
M Rosario
MR
Tito
Amelia
A