Stereoselective alkylidenation of ketones with 2-(p-toluenesulfinyl)benzyl iodide: synthesis of enantiomerically pure trisubstituted epoxides.
Alkylidenation of arylmethyl, dialkyl, and cyclic ketones with 2-( p-toluenesulfinyl)benzyl iodide in the presence of NaN(SiMe3)2 takes place with a high or complete control of the facial selectivity at the carbonyl group (up to 98% de) and the carbanion (>98% de), respectively, yielding mixtures of only two optically pure trisubstituted epoxides ( E/Z ratio ranges between 2:1 and >50:1). Removal of the p-tolylsulfinyl group with t-BuLi provides the corresponding (E)-3-phenyl-2,2-disubstituted epoxides without affecting their optical purity.
Arroyo
Yolanda
Y
Departamento de Química Orgánica (ETSII), Universidad de Valladolid, Valladolid, Spain. yarroyo@eis.uva.es
Meana
Angela
A
Sanz-Tejedor
M Ascensión
MA
Ruano
José Luis García
JL