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Highly Efficient Approach to 4‐Ethoxy‐5,6‐dihydro‐6,6‐disubstituted Pyran‐2‐ones using a Combinational Lewis Acid‐Base System
Author(s) -
Liu Jie,
Li Xing,
Wang Jun,
Feng Xiaoming
Publication year - 2006
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200505383
Subject(s) - chemistry , lewis acids and bases , pyran , ketone , base (topology) , carbon atom , quaternary carbon , medicinal chemistry , organic chemistry , stereochemistry , catalysis , ring (chemistry) , enantioselective synthesis , mathematical analysis , mathematics
Abstract The first efficient approach to 5,6‐dihydro‐6,6‐disubstituted pyran‐2‐ones was successfully achieved from the reaction between commercially available ethyl 3‐ethoxybut‐2‐enoate and ketones in the presence of BF 3 ⋅Et 2 O, InBr 3 and LDA. BF 3 ⋅Et 2 O and InBr 3 were employed as the Lewis acid to activate the ketone and LDA was employed as the Lewis base to activate ethyl 3‐ethoxybut‐2‐enoate. Aromatic, aliphatic, and heterocyclic ketones were converted to the corresponding δ‐lactones containing quaternary carbon atom centers in excellent yields (up to 99%) under mild conditions.