A new alkylation method of acetals has been developed by the reaction of the cationic intermediates, obtained by TESOTf-2,4,6-collidine treatment of acetals, followed by a Gilman reagent. The feature of the method is high chemoselectivity, which could not be attained by previously reported methods. Reaction proceeds under weakly basic conditions that acid-labile functional groups can tolerate.
Reaction of Acetals with Various Carbon Nucleophiles under Non-Acidic Conditions: CC Bond Formation via a Pyridinium-Type Salt
作者:Hiromichi Fujioka、Kenzo Yahata、Tomohito Hamada、Ozora Kubo、Takashi Okitsu、Yoshinari Sawama、Takuya Ohnaka、Tomohiro Maegawa、Yasuyuki Kita
DOI:10.1002/asia.201100812
日期:2012.2.6
substitution reactions of acetals with carbon nucleophilesvia the pyridinium‐type salts generated by the treatment of acetals with TESOTf‐2,4,6‐collidine or 2,2′‐bipyridyl have been developed. Various carbon nucleophiles, such as organocuprates, silyl enol ethers, enamines, etc., reacted with the pyridinium‐type salts to give the corresponding substituted products in good yields. The reactions proceeded