TMSCH(2)Li and TMSCH(2)Li-LiDMAE: efficient reagents for noncryogenic halogen-lithium exchange in bromopyridines.

作者信息

Doudouh Abdelatif, Woltermann Christopher, Gros Philippe C

机构信息

Synthèse Organométallique et Réactivité, UMR CNRS 7565, Nancy Université, Université Henri Poincaré, Boulevard des Aiguillettes, 54506 Vandoeuvre-lès-Nancy, France.

出版信息

J Org Chem. 2007 Jun 22;72(13):4978-80. doi: 10.1021/jo070620j. Epub 2007 May 25.

DOI:10.1021/jo070620j

PMID:17523672

Abstract

TMSCH(2)Li and TMSCH(2)Li-LiDMAE have been used efficiently for bromine-lithium exchange in 2-bromo-, 3-bromo-, and 2,5-dibromopyridines under noncryogenic conditions, while low temperatures (-78 to -100 degrees C) are always needed with n-BuLi. The aminoalkoxide LiDMAE induced a remarkable C-2 selectivity with 2,5-dibromopyridines in toluene at 0 degrees C, which was unprecedented at such a temperature. The lithiopyridines were successfully reacted with electrophiles also under noncryogenic conditions giving the expected adducts in good yields.

摘要