Authours: Jean-Luc Montchamp, Feng Tian, Matthew E. Hart, and J. W. Frost*
Journal: J. Org. Chem. 1996, 61, 3897-3899
After searching for an alternate protecting group for the protection of cis-dihydrocatechols, it was found that the butane-bisacetals were more resilient to hydrolysis. This is crucial when protecting group stabiity is required for acetals that are exposed to a range of conditions that may cause linear cis acetonide protected diols to fall apart. The numerous examplars, in the form of a table, highlight that this protecting group is has a broad application in selective diol protection. The detailed explantion and ease of text digestion makes this paper memorable for future syntheses.
The synthesis of the protecting group reagent, 2,2,3,3-tetramethoxybutane, was carried out on a multi-grams synthesis without any problems. Like described in the paper's experimental, the impure product could be used to protect the cis-diol starting material without a problem as the impurities and unreacted reagent was easily removed via column chromatography. The product obtained, after chromatography, exceeded yields of 80%. It was also found that the product crystalised upon sitting to deliver a X-ray crystal structure confiming the retention of the stereochemistry of the cis-diols.