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Formation of Five‐Membered Cyclic Orthoesters from Tribromides with Participation of a Neighboring Carbonyl Group
Author(s) -
Gururaja Guddeangadi N.,
Mobin Shaikh M.,
Namboothiri Irishi N. N.
Publication year - 2011
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201100042
Subject(s) - chemistry , orthoester , moiety , carbonyl group , conjugate , group (periodic table) , ketone , bromoform , organic chemistry , enone , medicinal chemistry , chloroform , mathematical analysis , mathematics
The Mg‐mediated conjugate addition of bromoform to enones followed by alcoholysis of the resulting keto tribromides proceeds through an unusual course, affording cyclic orthoester (dihydrofuran) intermediates under neutral workup conditions. However, acid workup of the reaction mixture or treatment of the isolated dihydrofurans with acid provides the expected but synthetically useful γ‐keto esters. The intermediacy of dihydrofurans in the one‐pot transformation of keto tribromides into γ‐keto esters provides evidence for the active participation of the neighboring carbonyl group in the alcoholysis of the tribromide moiety.