1,3-Dipolar Cycloadditions of Diazoalkanes to Activated Sulfoxides: Influence of Lewis Acids
作者:José L. García Ruano、M. Teresa Peromingo、Marina Alonso、Alberto Fraile、M. Rosario Martín、Amelia Tito
DOI:10.1021/jo051574v
日期:2005.10.1
The reactions of diazomethane and diazoethane with (S)-3-p-tolylsulfinylfuran-2(5H)-one (3) and its 4-methyl derivative (4) have been studied. The sulfinyl group was able to completely control the π-facial selectivity of all these reactions, which decreased when the polarity of the solvent increased and could be inverted in the presence of Lewis acids, Yb(OTf)3 being the most efficient catalyst. This
A New Entry to Enantiopure Polysubstituted Cyclopropanes: Stereoselective Denitrogenation of Sulfinylpyrazolines under Yb(OTf)<sub>3</sub> Catalysis
作者:José L. García Ruano、M. Teresa Peromingo、M. Rosario Martín、Amelia Tito
DOI:10.1021/ol061168d
日期:2006.7.1
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