TADDOL and its Analogues

In recent years, TADDOL and its analogues have found increasing use in organic chemistry these diols, derived from tartaric acid, were already successfully applied in catalysis as chiral ligands in metal complexes, furthermore, some of their syntheses were already optimized and their versatility was appreciated.  

asymmetric vinylogous aldol reactions could be effectively catalysed by diols 2 via hydrogen bonding, as shown by Rawal et al. in 2005 several 

The best results were obtained with 1-naphthyl-TADDOL 2a, but yields and ee values depended critically on the structure of the aldehyde although an excellent y-selectivity was always observed. In this case a ti-ti interaction between the electron-rich 1-naphthyl group and the electron-poor carbonyl group should further stabilize the hydrogen-bonded aldehyde, leaving the Re face accessible to nucleophile. 

In this latter work the X-ray structure of a complex TADDOL/aldehyde was reported for the first time to confirm the hypothesis of an intramolecular hydrogen bond between the two OH groups and an inter-molecular hydrogen bond between the other OH group and the oxygen of the carbonyl group. 

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