1.
Angew Chem Int Ed Engl
; 53(47): 12907-11, 2014 Nov 17.
Article
in English
| MEDLINE
| ID: mdl-25250907
ABSTRACT
The first examples of catalytic Wittig reactions with semistabilized and nonstabilized ylides are reported. These reactions were enabled by utilization of a masked base, sodium tert-butyl carbonate, and/or ylide tuning. The acidity of the ylide-forming proton was tuned by varying the electron density at the phosphorus center in the precatalyst, thus facilitating the use of relatively mild bases. Steric modification of the precatalyst structure resulted in significant enhancement of Eâ selectivity up to >95:5, E/Z.