Enantioselective synthesis and absolute configurations of aculeatins A, B, D, and 6-epi-aculeatin D

The three naturally occurring, bioactive spiroacetals aculeatins A, B, and D, as well as the non-natural 6-epi-aculeatin D have been synthesized for the first time in enantiopure form using an asymmetric allylation as the only chirality source. A further key step was a stereo-selective aldol reaction with remote induction. The absolute configurations of the natural products have been established and an erroneous structural assignment has been corrected. (c) 2006 Elsevier Ltd. All rights reserved.