Esters as Radical Acceptors: ß-NHC-Borylalkenyl Radicals Induce Lactonization by C-C Bond Formation/Cleavage on Esters.
Angew Chem Int Ed Engl
; 58(19): 6357-6361, 2019 May 06.
Article
in En
| MEDLINE
| ID: mdl-30891902
ABSTRACT
Substituted propargyl acetates are converted into 4-boryl-2(5H)-furanones upon thermolysis in the presence of an N-heterocyclic carbene borane (NHC-borane) and di-tert-butyl peroxide. The acetyl methyl group is lost during the reaction as methane. Evidence suggests that the reaction proceeds by a sequence of radical events including 1)â
addition of an NHC-boryl radical to the triple bond; 2)â
cyclization of the resultant ß-borylalkenyl radical to the ester carbonyl group; 3)â
ß-scission of the so-formed alkoxy radical to provide the 4-boryl-2(5H)-furanone and a methyl radical; and 4)â
hydrogen abstraction from the NHC-borane to return the initial NHC-boryl radical and methane.
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Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Angew Chem Int Ed Engl
Year:
2019
Document type:
Article
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