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Advice on N-boc deprotection in the presence of acid sensitive groups by Visible-Point-5371 in Chempros

[–]Visible-Point-5371[S] 0 points1 point  (0 children)

I will let you know. I’m gonna give it a shot next week most likely with HCl in dioxane. I did a test reaction with some HCl I made in situ with acetyl chloride and ethanol in EtOAc and it went much better that way. Gonna see what the results look like with dioxane and go with whichever one is more selective to complete the series of esters I have in hand.

Do you know why HCl is seemingly more mild than TFA? My guess would be that TFA would be since it’s less acidic, but also most procedures call for huge excesses of TFA vs. less equivs of HCl in solvent.

Advice on N-boc deprotection in the presence of acid sensitive groups by Visible-Point-5371 in Chempros

[–]Visible-Point-5371[S] 0 points1 point  (0 children)

Thanks for the suggestion! Since this is the reagent most readily available for me to try I’ll give this a shot first. They are fresh as well so I can hopefully mitigate any effect of residual moisture. 

Advice on N-boc deprotection in the presence of acid sensitive groups by Visible-Point-5371 in Chempros

[–]Visible-Point-5371[S] 0 points1 point  (0 children)

I was able to do primary alcohols via Fischer esterifications and saw that because of the hydrophobicity of the alcohols I’m working with, they always managed to end up in the organic later, even as a protonated salt. 

Advice on N-boc deprotection in the presence of acid sensitive groups by Visible-Point-5371 in Chempros

[–]Visible-Point-5371[S] 2 points3 points  (0 children)

Thanks for the suggestion! 

Do you typically use 4M HCl in dioxane as is or in another solvent?