The first convergent totalsynthesis of (+/-)-arisugacin A was accomplished by stereoselective construction of the arisugacin skeleton via a Knoevenagel-type reaction of an alpha,beta-unsaturated aldehyde with a 4-hydroxy 2-pyrone and stereoselective dihydroxylation followed by deoxygenation.
A 20-step total synthesis of (+/-)-arisugacin A with an overall yield of 2.1% is described here. This synthesis features highly convergent formal [3 + 3] cycloaddition and a strategic dihydroxylation-deoxygenation protocol leading to the desired angular C12a-OH. (C) 2002 Elsevier Science Ltd. All rights reserved.