Woodward group's synthesis of (G)-marasmic acid (Scheme 2) 37-39 commences with a completely endoselective Diels-Alder reaction of diene 9 and 2-(bromomethyl)maleic anhydride (8), yielding a mixture Scheme 1. Retrosynthetic analysis of marasmic acid.

Abstract-Methyl D-callipeltose 12 and D-callipeltose 4 were synthesized from D-glucal 5 in 10 and 11 steps, respectively. The synthesis features an azide displacement reaction of an a-nosyloxy ketone 7 and a highly diastereoselective C-methylation of a-azido ketone 8.

In the course of the synthesis of the DEFG ring system of cneorin C 1, we were faced with the task of preparing the furyl substituted allyl alcohol 5 enantioselectively. Several different methods starting from enantioselective zinc-mediated alkylations were attempted, but none of them proved entirely satisfactory. The solution turned out to be enzymatic kinetic resolution through a highly enantioselective (E > 300) acylation in the presence of Candida antarctica lipase A.