Thursday, December 13, 2007

deprotection of benzyl methyl ether.

1. BBr3.
popular.
2. BCl3, works for meta-carbonyl benzyl methyl ether.

3. alcl3,dcm
other ether can also be removed.

4. Et3SiH/(C6F5)3B then TBAF
very gentle condition.

5.HBr 48% solution, tributylhexdecylphosphonium bromide.
6. HBr, AcOH
7. PBr3.
conclusion: halide is essential. an oxygen-philic element is also important( usually an element with empty atomic orbitals).

7. LiCl/DMF/ heat
tolerates 1,2-diketone.

2 comments:

chandu...india said...

i have synthesized a mannose anchored quaternary ammonium salt with two long alkyl chains for my work. this mannose is protected with benzyl ether (4 -OBn except anomeric position). can u suggest me which would be better deprotecting agent for my compound other than catalytic hydrogenation or avoiding acetic acid.

Weiwei TIAN said...

If you can, oxidize the benzyl to benzoyl ester, then hydrolyze it.
RuO2/NaIO4.