American Chemical Society
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Phosphoric Acid-Catalyzed Asymmetric Synthesis of SPINOL Derivatives

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journal contribution
posted on 2016-12-02, 00:00 authored by Shaoyu Li, Ji-Wei Zhang, Xian-Lin Li, Dao-Juan Cheng, Bin Tan
Axially chiral 1,1′-spirobiindane-7,7′-diol (SPINOL) is the most fundamental and important privileged structure from which other chiral ligands containing a 1,1′-spirobiindane backbone are synthesized. Driven by the development of enantio­selective syntheses of axially chiral SPINOL derivatives, we have successfully developed the first phosphoric acid-catalyzed asymmetric approach. This approach is highly convergent and functional group tolerant, efficiently providing SPINOLs in good yield with excellent enantio­selectivity, thus delivering a practical and straightforward access to this privileged structure. It should be emphasized that the catalyst loading could be decreased to only 0.1 mol% for the preparative-scale synthesis. Furthermore, 4,4′-dimethyl-SPINOL-phosphoric acid was synthesized and applied to catalyze the model reaction for synthesis of enantio­enriched SPINOL derivatives.