TMSCH(2)Li and TMSCH(2)Li-LiDMAE: efficient reagents for noncryogenic halogen-lithium exchange in bromopyridines.
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.
Doudouh
Abdelatif
A
Synthèse Organométallique et Réactivité, UMR CNRS 7565, Nancy Université, Université Henri Poincaré, Boulevard des Aiguillettes, 54506 Vandoeuvre-lès-Nancy, France.
Woltermann
Christopher
C
Gros
Philippe C
PC
D001966:Bromine / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D018020:Lithium Compounds / Q000737:chemistry*; D015394:Molecular Structure; D011725:Pyridines / Q000138:chemical synthesis / Q000737:chemistry*; D014297:Trimethylsilyl Compounds / Q000737:chemistry*
D018020:Lithium Compounds; D011725:Pyridines; D014297:Trimethylsilyl Compounds; C073196:tetramethylsilane; D008094:Lithium; D001966:Bromine