Organic chemistry using weakly electrophilic salts: efficient formation of O,O-mixed, O,S- and N,O-acetals.
A mild and efficient method for the preparation of O,O-mixed, O,S- and N,O-acetals from symmetrical O,O-acetals has been developed. Thus, the treatment of symmetrical O,O-acetals with TESOTf and 2,4,6-collidine formed weakly electrophilic collidinium salts. The addition of nucleophiles, such as an alcohol, lithium thioxide, and sodium azide, to the salts afforded the corresponding O,O-mixed, O,S- and N,O-acetals in good yields. The reaction proceeded under weakly basic conditions. No overreaction then occurred and many acid-labile functional groups could remain intact.
Fujioka
Hiromichi
H
Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamada-oka, Suita, Osaka 565-0871, Japan. fujioka@phs.osaka-u.ac.jp
Okitsu
Takashi
T
Ohnaka
Takuya
T
Li
Ruichuan
R
Kubo
Ozora
O
Okamoto
Kazuhisa
K
Sawama
Yoshinari
Y
Kita
Yasuyuki
Y
D000080:Acetals / Q000138:chemical synthesis* / Q000737:chemistry; D002625:Chemistry, Organic / Q000379:methods*; D004563:Electrochemistry; D015394:Molecular Structure; D012492:Salts / Q000737:chemistry*
D000080:Acetals; D012492:Salts