Abstract
A systematic study for esterification procedures to the synthesis of BINOL diesters is described. Reaction conditions with trifluoracetic acid anhydride (TFAA) and 85% H3PO4 were selected as the best procedure to prepare enantiomerically pure (S)-1,1′-bi-2-naphthol (BINOL) diesters VIII to XI with almost quantitative yields and very short reaction times.
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GRAPHICAL ABSTRACT
ACKNOWLEDGMENTS
This work was supported by grants from ANPCyT (Buenos Aires, Argentina), CONICET (Buenos Aires, Argentina), and Universidad Nacional del Sur (Bahía Blanca, Argentina). A fellowship from CONICET to A. R. C. and G. M. S. is acknowledged.
Notes
a Inert atmosphere of Ar unless otherwise is indicated.
b Determined by TLC analysis.
c Determined by CG-MS analysis of crude reaction through a standard curve generated from isolated pure product.
d Method A.
e Method B.
f Method C.
g Method D.
h Method E.
i Unreacted BINOL and BINOL-monoester were observed.