Starting from inexpensive L-(+)-tartaric acid, it was possible to resolve and obtain pure both enantiomers oftrans-cyclohexane-1,2-diamine 1 and thence both enantiomers of BINOL 2, two of the most powerful, chiral inducing backbones in asymmetric catalysis. The modified method is very economic, not only due to an almost doubling of the overall yields of enantiomerically pure compounds (86% 1, 83% 2) but also due to the easy recovery of resolving agent 1 [66% (R,R)-1, 79% (S,S)-1] in the BINOL resolution. An improvement in the yield of the preparation of racemic BINOL is also recorded.
- Tartaric acid,
- Enantiomerically pure
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