Tetrahedron Letters

Alternative approaches to (Z)-1, 2-bis (2-bromopyridin-3-yl) ethenes, key intermediates in the synthesis of the 1, 10-phenanthroline core

G Chelucci, S Baldino, GA Pinna, B Sechi

Index: Chelucci, Giorgio; Baldino, Salvatore; Pinna, Gerard A.; Sechi, Barbara Tetrahedron Letters, 2008 , vol. 49, # 17 p. 2839 - 2843

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Citation Number: 2

Abstract

We have recently reported a new protocol for the synthesis of substituted 1,10-phenanthrolines 1, which serve as essentially universal ligands for metals, 1 by the de novo construction of the phenanthroline core (Scheme 1). 2 The approach is hinged upon the Ullmann intramolecular coupling of cis-1,2-bis(2-bromopyridin-3-yl)ethenes 2 that are in turn obtained by Wittig reaction of 2-bromonicotinaldehydes 3 with phosphonium salts 4 prepared from 2-bromo-3-( ...