Prelab to accompany bromination of trans-cinnamic acid (4 pts each) 2. Your TA a
ID: 1058960 • Letter: P
Question
Prelab to accompany bromination of trans-cinnamic acid (4 pts each)
2. Your TA and I want to see a prediction! Work out the probable stereochemistry of the product as part of the mechanism in your preparatory write-up. **Remember what a Fischer projection implies about the stereochemistry at each center. Models help tremendously here. Come prepared to discuss and defend your work during the pre-lab discussion.
Document 3 Microsoft Word Picture Tools Mailings Review Home Insert Page Layout iew Add References Format Compress Pictures Picture Bord Lth Bring Forward Align Send Backward Group Change Picture Picture Effects Remove Corrections Color Art Position Wrap Text Selection Pane A Rotate Effects Reset Picture Picture Layout Background Ad Pict Styl Arrange org Lab 343 INVESTIGATING THE STEREOCHEMISTRY OF BROMINE ADDITON TO AN ALKENE Introduction You already know from lecture that many alkene addition reactions evidence stereospecificity with either syn or anti addition being favored. In this experiment you will investigate the stereospecificity of bromine addition across a double bond. The proposed mechanism for the bromination ofan alkene involves the formation of a bromonium ion intermediate. Subsequent attack by bromide ion at the face opposite to the bromonium ion yield the product(s) of a addition. The overall reaction you will conduct is as follows: Br: CHCI, COOH HO 2,3-dibromo-3-phenylpropanoic acid irans-cinnamic acid mp 133°C Notice that the product contains 2 chiral centers. A non-stereospecific addition would result in 2 ....or 4 possible stereoisomers. On the other hand, a stereospecific addition limits the number of possible products to 2.... just one of the two enantiomeric pairs shown below. Which one is obtained is dependent upon whether the addition is syn or anti Page: 1 of 1 Words: 0 English (U.S I Height: 4.84 Crop Width: 6.71 100%Explanation / Answer
In organic chemistry
Cis addition+Cis alkene will give meso compound
Trans alkene+Trans addition will give meso compound.
Cis addition+Trans alkene will give racemic mixture
Cis alkene+Trans addition will give racemic mixture.
Here in your trans cinnamic acid (Trans alkene) and Trans addition will give meso 2,3 dibromo3-phenyl propanoic acid.