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Intramolecular Carbolithiation of Alkynes: anti Selectivity
Author(s) -
Fressigné Catherine,
Girard AnneLise,
Durandetti Muriel,
Maddaluno Jacques
Publication year - 2008
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.200704139
Subject(s) - acetal , intramolecular force , chemistry , alkene , lithium (medication) , triple bond , double bond , representation (politics) , stereochemistry , medicinal chemistry , lithium atom , computational chemistry , organic chemistry , psychology , catalysis , psychiatry , ion , politics , political science , law , ionization
A stereochemical twist in the tale : The treatment of the propargylic acetal 1 with one equivalent of n ‐butyllithium provided the dihydrobenzofuran 2 with an exocyclic E double bond. The results of DFT calculations suggest that strong coordination between the lithium cation and one oxygen atom of the acetal group drives the triple bond toward an E alkene. (A representation of the electron distribution near the transition state is shown on the right.)