Oxidation mechanisms and reagents

Dehydrogenation/elimination

alcohol → oxidization agent brings in LG to the OH → then a base is used to remove the H from the C and the bond goes to the O and the LG leaves (E2)

primary alcohols → aldehydes (r-c=o-h)

secondary alcohols → ketones (r-c=o-r)

Aldehyde to acid

Requires h2o

aldehyde → hydrate (double bond goes away, r-c-h(oh)2 → ox agent brings in LG → base takes H (E2) → end with a carboxylic acid

wet cr+6 oxidation Jones reagent

CrO3 + h2o + h2so4

wet cr+6 oxidation chromate

Na2cro4 + h2o + h2so4

wet cr +6 oxidation dichromate reagent

Na2cr2o7 +h2o + h2so4

Wet cr+6 oxidation requires h2o

Cr+6 is protonated (o=c=o-oh-oh2) → alcohol (oh takes the protonated Cr which becomes the LG) → h2o takes the H off the OH → h2o comes back in as a base then E2 → acid aldehyde → h2o is added → hydrate is created (O=C is broken & becomes (oh-c-oh-h-r) → same steps again → carboxylic acid

primary alcohol → acid aldehyde → carboxylic acid

secondary alcohol → ketone

Dry cr+6

used to make primary alcohol stop at aldehyde

Needs cr+6 and base

O takes the CrO3 as a LG → O becomes + and one of the O on Cr becomes a single bond & - charge → pyridine takes the H off of OH → the 2nd pyridine does E2 →acid aldehyde

primary alc → acid aldehyde

secondary alc → ketone

Dry cr+6 reagent

cro3 + 2 equiv. of pyridine (benzene with N in as atom in ring)

swern oxidation

2-steps

alcohol takes ox agent & becomes LG → Cl- takes H off of OH → Base takes most acidic H (Ch3) → electrons are added to the C-S → intramolecular elimination occurs (C NBE takes the H off of C-H then that bond goes to O and LG leaves

Primary → aldehyde

Secondary → ketone

swern oxidation reagent

DMSO ( ch3-s=o-ch3) + (Cl-c=o-c=o-cl) → ch3-s-cl-ch3 (ox agent)

Base: N(ch2ch3)3 N with 3 ethyl groups