4a: RSA Flashcards
What are common protecting groups for aldehydes and ketones and what are the reaction conditions for their additions?
Acetals, these are formed from 1,2-ethanediol and require an acid and magnesium sulphate to form.
What are common protecting groups for alcohols and what are the reaction conditions for their additions?
Silyl ethers (ROSiR3), specifically tert-butyldimethylsilyl (TBDMS) group. It deprotonates the alcohol using ClSiMe2tBu and base to clean up the HCl produced. It is removed using a source of fluorine such as Bu4NF (TBAF) to form O-, then worked up.
What are common protecting groups for amines and what are the reaction conditions for their additions?
Carbamates (RNHCO2R) which is added using ditBu carbonate. It is removed using TFA (trifluoroacetic acid).
What are common protecting groups for carboxylic acids and what are the reaction conditions for their additions?
Esters which are introduced using an alcohol and acid. They are removed using water and base followed by acid workup.
How do you convert an alkene to an alcohol, or a termial alkyne to an aldehyde?
BH3 then H2O2 and OH-
How do you convert a trans alkene to a trans dialcohol?
Percarboxylic acid then water and acid or base.
How do you convert a trans alkene to a cis alcohol?
KMnO4, OH- and water
OR
OsO4 and water
How do you convert an alkene to 2 aldehydes?
OsO4 and HIO4
OR
O3, low temp. then Me2S
How to you form an alkyne nucleophile?
NaNH2 and base
How do you form alkenes from carbonyls?
The Wittig reaction, Ph3P=CHR.
How do you convert a carbonyl to an alcohol?
LiAlH4 (strong) then H+
OR
NaBH4 (weak) then H+
How do you form imines?
Carbonyls and MeNH2
How do you form epoxides?
Alkenes plus percarboxylic acids.
What is the Heck reaction?
sp2 R-X + alkene → E alkene
Using Pd(0) catalyst and base
Where X = I or Br
