77332-85-5Relevant academic research and scientific papers
First regioselective c-2 lithiation of 3- and 4-chloropyridines
Choppin, Sabine,Gros, Philippe,Fort, Yves
, p. 603 - 606 (2007/10/03)
We have shown that the BuLi/LiDMAE reagent promotes the clean and regioselective C2 lithiation of 3- and 4-chloropyridines, while other reagents such as LDA or BuLi/TMEDA lead to classical ortho lithiation products or mixtures of regioisomers. The method was successfully applied to the preparation of various reactive 2,3- and 2,4-disubstituted pyridines.
REGIOSELECTIVE ORTHO-LITHIATION OF HALOPYRIDINES. SYNTHESES OF ORTHO-DISUBSTITUTED PYRIDINES AND A CONVENIENT GENERATION OF 3,4-PYRIDYNE
Gribble, Gordon W.,Saulnier, Mark G.
, p. 151 - 169 (2007/10/02)
The regioselective ortho-lithiation of 3-chloro- (4), 3-fluoro- (7), 3-bromo- (10), 2-chloro- (22), and 4-chloropyridine (25) with lithium diisopropylamide affords, after quenching with various electrophiles, the corresponding ortho-disubstituted pyridine
Synthesis and Synthetic Utility of 1-Acyl-5-(trialkylsilyl)-1,2-dihydropyridines. Synthesis of (+/-)-Elaeokanine A
Comins, Daniel L.,Myoung, Young Chan
, p. 292 - 298 (2007/10/02)
The regioselective addition of Grignard reagents to the phenoxycarbonyl salts of 3-(trialkylsilyl)pyridines was studied.Most of the 3-(trialkylsilyl)pyridine salts gave a mixture of dihydropyridines on reaction with aliphatic Grignard reagents.However, al
Directed Lithiation of 4-Halopyridines: Chemoselectivity, Regioselectivity and Application to Synthesis
Marsais, F.,Trecourt, F.,Breant, P.,Queguiner, G.
, p. 81 - 87 (2007/10/02)
4-Chloro and 4-fluoropyridines were ortho-lithiated by n-butyllithium-TMEDA chelate or lithium diisopropylamide at low temperature.The resulting 3-lithio 4-halopyridines were reacted with electrophiles which led to various 3,4-disubstituted pyridines.The versatility of this functionalization is enhanced by the 4-halogen reactivity towards nucleophiles such as water, methylate and amines.Some of the 3,4-disubstituted synthons were annelated to naphthyridine, xanthone and coumarin or condensed to Hantzsch-ester or to "chlotrimazol" analogues.Lithiation of 4-fluoropyridine led in one step to 3,4-pyridyne, which was trapped by cycloaddition with furans.
Regioselective ortho lithiation of halopyridines
Gribble, Gordon W.,Saulnier, Mark G.
, p. 4137 - 4140 (2007/10/02)
Regioselective ortho lithiation of 2-, 3-, and 4-halopyridines is achieved with lithium diisopropylamide (-78°, tetrahydrofuran) to afford, upon quenching with electrophilic reagents, 2,3- and 3,4-disubstituted pyridines in good to excellent yield.
