Expedient, high-yielding synthesis of silyl-substituted salen ligands.
Described is an efficient synthesis of silyl-substituted salen ligands, used for the preparation of enantioselective catalysts. The salicylaldehyde precursors are synthesized from the silyl ethers of 2,6-dibromophenols via a one-pot double lithium halogen exchanges, to induce an intramolecular retro-Brook rearrangement and allow introduction of the aldehyde group. Condensation of the salicylaldehyde products with a chiral diamine affords the silyl-substituted salen ligands in high yields. The use of other electrophiles allows easy access to silyl-substituted phenolic esters, ketones, and boronic acids.
Thadani
Avinash N
AN
Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, USA.
Huang
Yong
Y
Rawal
Viresh H
VH
D000447:Aldehydes / Q000737:chemistry; D005029:Ethylenediamines / Q000138:chemical synthesis* / Q000737:chemistry; D008024:Ligands; D008745:Methylation; D015394:Molecular Structure
D000447:Aldehydes; D005029:Ethylenediamines; D008024:Ligands; C013243:salicylaldehyde; C011452:disalicylaldehyde ethylenediamine