Hon SW, Li CH, Kuo JH, Barhate NB, Liu YH, Wang Y, Chen CT. Catalytic asymmetric coupling of 2-naphthols by chiral tridentate oxovanadium (IV) complexes.
Org Lett 2001;
3:869-72. [PMID:
11263903 DOI:
10.1021/ol015505o]
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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%.
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