Regioselective diversification of a cardiac glycoside, lanatoside C, by organocatalysis
Yoshihiro Ueda1, Kenji Mishiro, Keisuke Yoshida
1Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
Abstract:
Acylation of lanatoside C in the presence of organocatalyst 5 gave the C(4'''')-O-acylate in up to 90% regioselectivity (catalyst-controlled regioselectivity). Various functionalized acyl groups can be introduced at the C(4'''')-OH by a mixed anhydride method in the presence of 5 or the related organocatalyst. On the other hand, DMAP-catalyzed acylation of lanatoside C gave the C(3'''')-O-acylate in up to 97% regioselectivity (substrate-controlled regioselectivity). Thus, diverse regioselective introduction of acyl groups among eight free hydroxy groups of lanatoside C was achieved.
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