Method for producing, via organometallic compounds, organic intermediate products
The present invention provides a process for preparing aryllithium compounds by reacting haloaliphatics with lithium metal to form a lithium alkyl and reacting the lithium alkyl with aromatic halogen compounds of formula (III) in a halogen-metal exchange reaction to form the corresponding lithium aromatics of formula (IV).
1 . A process for preparing aryllithium compounds comprising the steps of:
1) reacting at least one haloaliphatic compound of formula (I) with lithium metal to form a lithium alkyl of formula (II); and
2) reacting the lithium alkyl of formula (II) with at least one aromatic halogen compound of formula (III) in a halogen-metal exchange reaction to form a lithium aromatic of formula (IV),
where R is methyl, a primary, secondary or tertiary alkyl radical having from 2 to 12 carbon atoms,
Hal 1 =fluorine, chlorine, bromine or iodine,
Hal 2 =chlorine, bromine or iodine,
X 1-5 are, independently of one another, each carbon or one or more moieties
X 1-5 R 1-5 is nitrogen or two adjacent radicals X 1-5 R 1-5 can together be O, S, NH or NR′, where R′ is C 1 -C 5 -alkyl, SO 2 -phenyl, SO 2 -p-tolyl or benzoyl;
the radicals R 1-5 are substituents selected from the group consisting of hydrogen, methyl, primary, secondary or tertiary, cyclic or acyclic alkyl radicals having from 2 to 12 carbon atoms.
2 . The process as claimed in claim 1 , wherein the process is carried out at temperatures in the range from −100 to +25° C.
3 . The process as claimed in claim 1 , wherein the at least one haloaliphatic compound is selected from the group consisting of chlorocyclohexane, bromocyclohexane, benzyl chloride, chlorohexanes and chloroheptanes.
4 . The process as claimed in claim 1 , wherein the amount of lithium to be added per mole of halogen to be reacted is in the range from 1.95 to 2.5 mol.
5 . The process as claimed in claim 1 , wherein the process is carried out in an ether solvent.
6 . The process as claimed in claim 1 , wherein organic redox systems are added in the process.
7 . The process as claimed in claim 1 , further comprising the step of reacting the lithium aromatic of formula (IV) with an electrophile.
8 . The process as claimed in claim 7 , wherein the process is carried out as a one-pot reaction and the electrophile is added to the reaction mixture at the same time as the at least one aromatic halogen compound of formula (III).
9 . The process as claimed in claim 7 , wherein the electrophile is a compound selected from the group consisting of carbon, boron and silicon compounds.
10 . The process as claimed in claim 1 , wherein, in which one or more hydrogen atoms of R 1-5 is replaced by fluorine, substituted cyclic or acyclic alkyl groups, alkoxy, dialkylamino, alkylamino, arylamino, diarylamino, phenyl, substituted phenyl, alkylthio, diarylphosphino, dialkylphosphino, dialkylaminocarbonyl or diarylaminocarbonyl, monoalkylaminocarbonyl, monoarylaminocarbonyl, CO 2 − , hydroxyalkyl, alkoxyalkyl, or chlorine.
11 . The process as claimed in claim 1 , wherein two adjacent radicals R 1-4 can together correspond to an aromatic or aliphatic fused-on ring.
12 . The process as claimed in claim 1 , wherein R is substituted by a radical selected from the group consisting of phenyl, substituted phenyl, aryl, heteroaryl, alkoxy, dialkylamino, alkylthio}, substituted alkyl or substituted or unsubstituted cycloalkyl having from 3 to 8 carbon atoms.