Monday, March 31, 2008

THP ether protective group

Tetrahydrohydropyranyl (THP) ether
is not a leaving group. stable under basic conditions.
can't eliminate even bata to Grigyard anion.

Formation:
catalytic amount of con. HCl + alcohol + 3,4-dihydro-2H-pyran
no solvent. 0 C to rt. overnight.
CeCl3-7H2O 5%, NaI 5%, no solvent. 1-10hr. a new way to make the thp ether.

deprotection:
1. TsOH in EtOH/MeOH.

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