For 10 points, what is this reaction that forms olefins from ketones and phosphonium ylides, named after a German chemist?
Although Georg Geissler was the second author on the paper introducing this reaction, he is never referred to as a namesake of this reaction. One alternative to this reaction uses a compound obtained in the Arbuzov rearrangement; that alternative transforms carbanions into olefins with E-selectivity and is named after Emmons, Wadsworth, and Horner. Another modification to this reaction adds lithium salts to create the threo version of the betaine intermediate, which again creates E-selectivity, instead of the usual Z-selectivity, in the product of that Schlosser modification. For 10 points, what is this reaction that forms olefins from ketones and phosphonium ylides, named after a German chemist?
Although Georg Geissler was the second author on the paper introducing this reaction, he is never referred to as a namesake of this reaction.
Wittig reaction [or Wittig olefination]