Holot CH3 H3C Ph₂p-CHCH3 Aldehydes and ketones are converted into alkenes by means of a direct nucleophilic addition called the Wittig reaction. In the reaction, a triphenylphosphorine ylide, also called a phosphorane, adds to an aldehyde/ketone to give a four-membered cyclic intermediate called an oxaphosphetane. The oxaphosphetane is not isolated but instead spontaneously decomposes to release triphenylphosphine oxide and an alkene. L CXT CH3 H₂C Br-CH₂CH3 :PPh3 The ylide is formed by reaction of triphenylphosphine, a good nucleophile, with a primary alkyl halide in an SN2 reaction, followed by deprotonation of the carbon with a strong base, such as butyllithium. The carbonyl carbon and the carbon originally bonded to the halogen become the two carbons with the double bond in the product alkene CH3 The real value of the Wittig reaction lies in its ability to yield an alkene of predictable structure, as the C=C bond is precisely where the C-O bond was in the reactant and no isomers (other than E/Z isomers) are formed. Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions Ph3P-CH₂CH3 Br Ph3P=O 76

Chemistry
10th Edition
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Chapter1: Chemical Foundations
Section: Chapter Questions
Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
icon
Related questions
Question
100%
Ph3P-CHCH3
H₂C
H3C
Aldehydes and ketones are converted into alkenes by means of a direct nucleophilic addition called the Wittig reaction. In the reaction, a triphenylphosphorine ylide, also called a phosphorane, adds to
an aldehyde/ketone to give a four-membered cyclic intermediate called an oxaphosphetane. The oxaphosphetane is not isolated but instead spontaneously decomposes to release triphenylphosphine
oxide and an alkene.
CH3
00
+
The ylide is formed by reaction of triphenylphosphine, a good nucleophile, with a primary alkyl halide in an SN2 reaction, followed by deprotonation of the carbon with a strong base, such as
butyllithium. The carbonyl carbon and the carbon originally bonded to the halogen become the two carbons with the double bond in the product alkene
X m
CH3
The real value of the Wittig reaction lies in its ability to yield an alkene of predictable structure, as the C=C bond is precisely where the C=O bond was in the reactant and no isomers (other than E/Z
isomers) are formed.
Draw curved arrows to show the movement of electrons in this step of the mechanism.
Arrow-pushing Instructions
Br-CH₂CH3 :PPh3
CH3 + Ph3P=O
Ph3p- -CH₂CH3 Br
76
Transcribed Image Text:Ph3P-CHCH3 H₂C H3C Aldehydes and ketones are converted into alkenes by means of a direct nucleophilic addition called the Wittig reaction. In the reaction, a triphenylphosphorine ylide, also called a phosphorane, adds to an aldehyde/ketone to give a four-membered cyclic intermediate called an oxaphosphetane. The oxaphosphetane is not isolated but instead spontaneously decomposes to release triphenylphosphine oxide and an alkene. CH3 00 + The ylide is formed by reaction of triphenylphosphine, a good nucleophile, with a primary alkyl halide in an SN2 reaction, followed by deprotonation of the carbon with a strong base, such as butyllithium. The carbonyl carbon and the carbon originally bonded to the halogen become the two carbons with the double bond in the product alkene X m CH3 The real value of the Wittig reaction lies in its ability to yield an alkene of predictable structure, as the C=C bond is precisely where the C=O bond was in the reactant and no isomers (other than E/Z isomers) are formed. Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions Br-CH₂CH3 :PPh3 CH3 + Ph3P=O Ph3p- -CH₂CH3 Br 76
Expert Solution
steps

Step by step

Solved in 3 steps with 1 images

Blurred answer
Knowledge Booster
Carboxylic Acids and their Derivatives
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, chemistry and related others by exploring similar questions and additional content below.
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
Chemistry
Chemistry
Chemistry
ISBN:
9781305957404
Author:
Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:
Cengage Learning
Chemistry
Chemistry
Chemistry
ISBN:
9781259911156
Author:
Raymond Chang Dr., Jason Overby Professor
Publisher:
McGraw-Hill Education
Principles of Instrumental Analysis
Principles of Instrumental Analysis
Chemistry
ISBN:
9781305577213
Author:
Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:
Cengage Learning
Organic Chemistry
Organic Chemistry
Chemistry
ISBN:
9780078021558
Author:
Janice Gorzynski Smith Dr.
Publisher:
McGraw-Hill Education
Chemistry: Principles and Reactions
Chemistry: Principles and Reactions
Chemistry
ISBN:
9781305079373
Author:
William L. Masterton, Cecile N. Hurley
Publisher:
Cengage Learning
Elementary Principles of Chemical Processes, Bind…
Elementary Principles of Chemical Processes, Bind…
Chemistry
ISBN:
9781118431221
Author:
Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:
WILEY