Direct zincation of functionalized aromatics and heterocycles by using a magnesium base in the presence of ZnCl2.
A wide range of polyfunctional aryl and heteroaryl zinc reagents were efficiently prepared in THF by using (TMP)(2)Mg2 LiCl (TMP=2,2,6,6-tetramethylpiperamidyl) in the presence of ZnCl(2). The possible pathways of this metalation procedure as well as possible reactive intermediates are discussed. This experimental protocol expands the tolerance of functional groups and allows an efficient zincation of sensitive heterocycles such as quinoxaline or pyrazine. The zincated arenes and heteroarenes react with various electrophiles providing the expected products in 60-95 % yield.
Dong
Zhibing
Z
Department Chemie und Biochemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 Haus F, 81377 München, Germany.
Clososki
Giuliano C
GC
Wunderlich
Stefan H
SH
Unsinn
Andreas
A
Li
Jinshan
J
Knochel
Paul
P
D002712:Chlorides / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D000077489:Piperazine; D010879:Piperazines / Q000737:chemistry; D011522:Protons; D015032:Zinc / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry*
D002712:Chlorides; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; D010879:Piperazines; D011522:Protons; D017967:Zinc Compounds; D000077489:Piperazine; C016837:zinc chloride; D008274:Magnesium; D015032:Zinc