Enantioselective intramolecular cyclization of alkynyl esters catalyzed by a chiral Br?nsted base
An enantioselective intramolecular cyclization reaction of alkynyl esters was developed, which employs a Br?nsted base catalyst generated in situ from a chiral Schiff base and t-BuOK. This reaction is a rare example of the enantioselective intramolecular addition of simple ester enolates to alkynes under Br?nsted base catalysis.
Kondoh, Azusa,Tran, Hoa Thi Quynh,Kimura, Kyoko,Terada, Masahiro
p. 5726 - 5729
(2016/05/19)
Gold-catalyzed cyclizations of (o-alkynyl)phenoxyacrylates with external nucleophiles: Regio-and stereoselective synthesis of functionalized benzo[b]oxepines
A catalytic approach to benzo[b]oxepines with high stereoselectivity by Au-catalyzed cyclization of (o-alkynyl)phenoxyacrylates with various nucleophiles under mild reaction conditions has been developed. Notably, the use of vinyl ether instead of alcohol could afford the same benzoxepines. The reaction may proceed by Au-catalyzed oligomerization of vinyl ether to release the alcohol, which then reacts with (o-alkynyl)phenoxyacrylates to furnish the benzoxepines.
Liu, Jun,Liu, Yuanhong
p. 4742 - 4745,4
(2020/09/16)
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