abstract
The BF3-directed lithiation of 3-chloro- and 3-bromopyridine (1a and 1b, espectively) has been investigated. The reactions of 3-chloro- or 3-bromopyridine-BF3 adduct with LDA (1.3/1.1 equiv) followed by quenching with benzaldehyde or iodine exclusively gave the C-2 substituted products. However, when 2.2 equiv of LDA and dimethyl disulfide was used, a C-6 substituted product was obtained. Dilithiation of 1a and 1b has been studied with and without the involvement of BF3 complexation. The role of Li...F(BF3) interactions has been investigated by experimental and DFT calculations. (C) 2013 Elsevier Ltd. All rights reserved.
keywords
REGIOSELECTIVE ORTHO-LITHIATION; DENSITY-FUNCTIONAL THEORY; HALOGEN-LITHIUM EXCHANGE; X-RAY-STRUCTURE; C-2 LITHIATION; TMSCH2LI-LIDMAE; BROMOPYRIDINES; METALATION; HALOPYRIDINES; PYRIDINES
subject category
Chemistry
authors
Dhau, JS; Singh, A; Kasetti, Y; Bhatia, S; Bharatam, PV; Brandao, P; Felix, V; Singh, KN
our authors
Paula Cristina Ferreira da Silva Brandão
Assistant Researcher
Vítor Félix
Associate Professor with AggregationGroups
1 - inorganic functional nanomaterials and organic-inorganic hybrids
6 - computer simulation and multiscale modeling
acknowledgements
We are thankful to the CSIR, New Delhi, India, for financial support. Additional support from SAP by UGC, New Delhi, is also acknowledged. We are also thankful to Mr. Avtar Singh, CIL, Punjab University, Chandigarh, for NMR spectra.