title: The syntheses of new camphorsulfonylated ligands derived from 2-amino-2'-hydroxy-1,1'-binaphthyl and their enantioselectivities in the addition of dialkylzinc reagents to aldehydes.
abstract: A series of new camphorsulfonylated ligands derived from chiral 2-amino-2'-hydroxy-1,1'-binaphthyl (NOBIN) and (+)-camphorsulfonic acid were synthesized by a short and simple synthetic sequence, and their enantioselective catalytic activities were assessed in the nucleophilic addition reaction of dialkylzinc reagents to aldehydes in the presence of titanium tetraisopropoxide. The most efficient ligand, N-hydroxycamphorsulfonylated (S)-NOBIN, gave (S)-addition products with good yields and up to 87% of ee value. The (1)H nuclear magnetic resonance (NMR) and (13)C NMR results of the titanium titration experiments on this ligand indicate that the most likely catalytic reactive species involved in this catalytic asymmetric addition is a bimetallic titanium complex. A possible catalytic reaction mechanism is proposed.
authors: The Key Laboratory of Coal to Ethylene Glycol and Its Related Technology, Chinese Academy of Sciences, Fuzhou, Fujian, China.
authors: Guangling
authors: G
authors: Bian
authors: Huayin
authors: H
authors: Huang
authors: Hua
authors: H
authors: Zong
authors: Ling
authors: L
authors: Song
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D002164:Camphor / Q000138:chemical synthesis / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry*; D013237:Stereoisomerism; D013449:Sulfonamides / Q000138:chemical synthesis / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D008024:Ligands; D009281:Naphthalenes; D013449:Sulfonamides; D002164:Camphor; D014025:Titanium; D015032:Zinc; C412330:1,1'-binaphthyl