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Organocatalytic Chemo- and Regioselective Acylation of Monosaccharides
T. Kawabata*, W. Muramatsu, T. Nishio, T. Shibata, H. Schedel
Kyoto University, Japan
22 November 2007 (online)
The presented organocatalyst allows for the regio- and chemoselective acylation of the equatorial hydroxy group at carbon C(4) of monosaccharides. This is especially remarkable since the substrates not only contain a primary hydroxyl group but also two other secondary alcohols. The catalyst of choice contains a DMAP-type subunit as the active center and two tryptophans as directing groups. It mediates the acylations with usually high yields and in often excellent regioselectivities. Mechanistic studies and transition-state models to explain the observed selectivities have been included in the paper.