Catalytic Asymmetric Coupling of 2-Naphthols by Chiral Tridentate Oxovanadium(IV) Complexes

Abstract

A series of chiral oxovanadium(IV) complexes derived from tridentate N-3,5-substituted and N-3,4-benzo- and N-5,6-benzo-salicylidene-alpha-amino acids can serve as efficient catalysts for the enantioselective oxidative couplings of various 3-, 6-, and 7-substituted 2-naphthols under O(2). The best scenario involves the use of a vanadyl complex arising from 2-hydroxy-1-naphthaldehyde and valine (or phenylalanine) in CCl(4), leading to BINOLs in good yields (75-100%) and with enantioselectivities of up to 68%.

Thirty years through vanadium chemistry

“…As mentioned above, other researchers made also relevant contributions in this same field, such as Fujita [105], Rehder [110,111,130,131], Casella [132], Chakravorty [112,113,[133][134][135], and others [136][137][138], in some cases reporting peculiar characteristics of the compounds or catalytic activity.…”

Recent advances in asymmetric oxidative coupling of 2‐naphthol and its derivatives

“…Independently, Chen and coworkers 48 designed and synthesized a series of chiral oxovanadium (IV) complexes 19,20, and 21 derived from tridentate N-3,5-substituted, N-3,4-benzo-, and N-5,6-benzo-salicylidene-a-amino acids, respectively (Scheme 11). These chiral complexes can serve as efficient catalysts for asymmetric oxidative coupling of various 2-naphthols derivatives under O 2 .…”

Electrospray mass spectrometry and tandem mass spectrometry of bimetallic oxovanadium complexes

“…These complexes exhibit attractive promise as orally available treatments for diabetes mellitus and also have a number of applications as catalysts in various oxidation reactions [1][2][3][4][5][6][7][8][9][10]. Recently, some oxovanadium complexes, especially bimetallic oxovanadium complexes of chiral Schiff bases reported by Gong's group, were shown to provide high enantioselectivity for the oxidative coupling of 2-naphthols, which play very important roles in the history of asymmetric synthesis [11][12][13][14][15][16][17].Structural characterization of the bimetallic oxovanadium complexes is key to the further development of their functions. Nuclear magnetic resonance (NMR) spectroscopy eH and SlV) can provide abundant information for structural analyses of bimetallic oxovanadium complexes.…”