I am writing a paper on an article and it shows many different compounds and I want a better understanding of where each originated and what steps were made in their synthesis. I would also like to know how to write a mechanism for this reaction.
When (4R,4S)-hydroxy-4-(4'-nitrophenyl)butan-2-one is in methylene chloride at -78 degrees celsius and diethylaminosulfur triflouride was added it yielded (4R,4S)-flouro-4-(4'-nitrophenyl)butan-2-one.
I have tried many different ways and they seem to not be working. I guess I just don't fully understand this reaction.© BrainMass Inc. brainmass.com October 5, 2022, 12:57 am ad1c9bdddf
SOLUTION This solution is FREE courtesy of BrainMass!
This is not strictly an elimination reaction - it is a fluorination reaction :)
I have attached the mechanism for you. For your interest, this sulfur reagent is known as DAST in organic synthesis
In terms of your R,S assignment, that carbon (highlighted in the attachment with an asterix), can be R or S not both. the important this for you is, if you start with an R-alcohol, you end up with an S fluoride and vice versa - this is because the substition is an SN2 substitution of fluoride so inverts the stereochemisry.
n.b. If you meant 4R,4S to be racemic then yes you are right, you would end up with a racemic (mixture of R and S) product mixture
I hope this helps you.
All the best and good luck,
Dr Alan Robinson, PhD© BrainMass Inc. brainmass.com October 5, 2022, 12:57 am ad1c9bdddf>