Organic Chemistry : Help with Wittig Reactions
Study concepts, example questions & explanations for Organic Chemistry
All Organic Chemistry Resources
Example Questions
Example Question #1 : Help With Wittig Reactions
What is the final organic product of the reaction shown?
IV
V
III
I
II
III
First step: esterification
Second step: reduction
Third step: neutralization
Fourth step: oxidation to aldehyde
Fifth step: alkene metathesis
Example Question #1 : Reactions With Ketones And Aldehydes
All of the following are characteristics of a Wittig reaction except __________.
it produces a trialkylphosphine oxide or triarylphosphine oxide as a by-product
it results in the formation of a carbon-carbon double bond
it involves the reaction of a phosphonium ylide with a carbonyl
it results in the exclusive formation of trans double bonds
it proceeds through a phosphaoxetane intermediate
it results in the exclusive formation of trans double bonds
The Wittig reaction involves the reaction of a phosphonium ylide (generated by treating a phosphonium salt with a strong base) with a ketone or aldehyde.
The reaction proceeds through a phosphaoxetane (4-membered ring containing both phosphorus and oxygen) intermediate to generate a new compound containing a carbon-carbon double bond, plus a phosphine oxide byproduct. It does not form trans double bonds exclusively; sometimes, a mixture of cis and trans isomers are obtained, and sometimes the cis isomer is the predominant product.
All Organic Chemistry Resources
