Octalactin A, an antitumor agent containing an eight-membered lactone moiety, has been stereoselectively prepared by means of enantioselective aldol reactions of selected silyl enolates with achiral aldehydes, promoted by a chiral Sn(II) complex. The medium-sized lactone part was effectively constructed by way of a new and rapid mixed-anhydride lactonization using 2-methyl-6-nitrobenzoic anhydride (MNBA) with a catalytic amount of 4-(dimethylamino)pyridine (DMAP) or 4-(dimethylamino)pyridine 1-oxide (DMAPO). The use of only 5 mol % of DMAP or 2 mol % of DMAPO rapidly promoted formation of the medium-sized ring of the octalactin, demonstrating the remarkable efficiency of the new lactonization protocol.

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An efficient method for the synthesis of (+)-buergerinin F is established via the enantioselective aldol reaction of a tetra-substituted ketene silyl acetal with crotonaldehyde, followed by intramolecular Wacker-type ketalization.

Drug design using boron‐containing heterocycles has attracted a great deal of attention because these compounds are believed to possess high biological activity. However, information on the synthetic methodology and pharmacokinetic profiling of boron‐containing compounds is limited. In this study, we provide a new synthetic route for preparation of spiro‐fused benzoxaborin derivatives and investigate their in vitro pharmacokinetic properties. Our efforts led to the successful construction of a chemical library of spiro‐fused benzoxaborin derivatives with appropriate physicochemical and in vitro pharmacokinetic properties for oral drugs. These results indicate that the synthesized boron‐containing compounds are therefore eligible for classification in a novel chemical library.

The first total synthesis of (–)-merrillianin (1), which is a natural sesquiterpene with a tri- fused structure having a cyclopentane ring and five- and seven-membered lactone parts, is demonstrated. This asymmetric total synthesis enabled the absolute stereo structure determination of naturally occurring (–)-1.