Catalytic asymmetric oxidative couplings of 2-naphthols by tridentate N-ketopinidene-based vanadyl dicarboxylates.
[reaction: see text] A series of oxovanadium(IV) complexes derived from tridentate N-ketopinidene-alpha-amino acids were synthesized. They serve as efficient catalysts for the enantioselective oxidative couplings of various 3-, 6-, or 7-substituted 2-naphthols. The best scenario involves the use of a vanadyl complex arising from L-tert-leucine in CCl4. The asymmetric couplings of 2-naphthols can be conducted smoothly at 40-45 degrees C under a stream of gaseous oxygen, leading to 2,2'-dihydroxy-1,1'-binaphthyls in good yields (61-99%) and with enantioselectivities of up to 87%.
Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan.
Nivrutti B
NB
Barhate
Chien-Tien
CT
Chen
D000596:Amino Acids / Q000737:chemistry; D001952:Bridged-Ring Compounds / Q000737:chemistry; D002384:Catalysis; D019281:Dimerization; D007659:Ketones / Q000737:chemistry; D009284:Naphthols / Q000138:chemical synthesis* / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D014638:Vanadates / Q000737:chemistry
D000596:Amino Acids; C406944:BINOL, naphthol; D001952:Bridged-Ring Compounds; D007659:Ketones; D009284:Naphthols; C431983:ketopinic acid; C075743:oxovanadium IV; D014638:Vanadates; C028405:2-naphthol; D010100:Oxygen