Chapter 19 October 19 - reactivity, and allows for an...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Wittig Reaction: Mechanism of Addition Symmetrical Ketone:
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Wittig Reaction: Mechanism of Addition Aldehydes and Unsymmetrical Ketones:
Background image of page 2
3 Wittig Reaction Practice Problems:
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 Wittig reaction E/Z selectivity: General Rule : Wittig reagents with anion­stabilizing substituents, such as a carbonyl group, adjacent to the negative charge are called "stabilized ylides." These are E selesctive. Unstabilized ylides (without adjacent anion stabilizing groups) are Z selective Stabilization of the ylide through resonance decreases its
Background image of page 4
Background image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: reactivity, and allows for an equilibrium to be established during the product determining step that favors the more stable E isomer. 5 HornerEmmonsWadsworth Modification: Uses a phosphonate ester derived from an haloester or ketone to generate the Wittig carbanion Treatment of the phosphonoester with a strong base followed by an aldehyde or ketone gives an alkene, in this case an , unsaturated ester, ketone, or aldehyde The resulting alkene is almost entirely the E isomer:...
View Full Document

This note was uploaded on 12/20/2011 for the course CHEM 234-54 taught by Professor Morrison during the Fall '09 term at University of Georgia Athens.

Page1 / 5

Chapter 19 October 19 - reactivity, and allows for an...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online