A convenient method for removal of the t-butyl group from nucleoside bis(t-butyl) phosphates under non-acidic conditions
✍ Scribed by Mitsuo Sekine; Shin Iimura; Takeshi Nakanishi
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- French
- Weight
- 248 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0040-4039
No coin nor oath required. For personal study only.
✦ Synopsis
A new method for selective removal of the t-butyl group from 3'bis(t-butyl) phosphate esters of 5'-O-(4,4'-dimethoxytrityl)deoxyribonucleosides was developed by use of Me&iCl and Et=N. Several unexpected properties of the t-butyl group were described.
Quite recently, Johnslez has reported di-t-butyl N,N-diethylphosphoramidite (BEPA) as a new phosphitylating agent for phosphorylation of alcohols. This reaction gave cleanly bis(t-butyl) alkyl phosphates in high yields. However, its removal for conversion to unesterified monoalkyl phosphates required rather drastic acidic conditions such as 1 M HCl/dioxanc, r.t., 4 hl and 6-90 % trifluoroacetic acid/benzene or CH2C11, r.t., 24 h."-" This is only a drawback when the t-butyl group is considered to be used as an phosphate protecting group in the synthesis of acid-sensitive natural products containing phosphates.