Efficient Routes to Racemic and Enantiomerically Pure (S)-BINOL Diesters

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.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications^® for the following free supplemental resources: Full experimental and spectral details.]

GRAPHICAL ABSTRACT

Keywords:

• BINOL
• C₂ symmetry
• diesters
• diols
• esterification
• phase-transfer catalysis

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.