Total Synthesis of a Diacetonide Derivative of Thuggacin A

A highly stereoselective total synthesis of the diacetonide derivative of the antibiotic thuggacin A has been described. The synthesis features the stereoselective Stille cross-coupling reaction to set up the whole carbon framework, aldol condensation to construct the highly substituted conjugated diene, non-Evans <i>syn</i> aldol, CBS reduction, Hantzsch’s thiazole synthesis, Horner–Wadsworth–Emmons reaction, and Shiina’s macrolactonization

Total Synthesis and Stereochemical Revision of 4,8-Dihydroxy-3,4-dihydrovernoniyne

The first asymmetric total synthesis of two possible diastereomers (4<i>S</i>,5<i>R</i>)-4,8-dihydroxy-3,4-dihydrovernoniyne <b>5</b> and (4<i>S</i>,5<i>S</i>)-4,8-dihydroxy-3,4-dihydrovernoniyne <b>5a</b> is accomplished. Salient features of the synthesis involve Cadiot–Chodkiewicz coupling and Sonogashira cross-coupling of terminal acetylenes. Detailed comparison of the ¹H and ¹³C NMR data and specific rotation with that of the natural product led to the revision of the absolute stereochemistry of the natural product as (4<i>S</i>,5<i>S</i>)-4,8-dihydroxy-3,4-dihydrovernoniyne <b>5a</b>

Asymmetric Total Synthesis of the Putative Structure of Diplopyrone

The first asymmetric total synthesis of the putative structure of diplopyrone was achieved in 17 linear steps starting from <i>cis</i>-1,4-butene-diol. The synthetic route features iodine-catalyzed tandem isomerization followed by C–O and C–C bond formation reaction strategy developed by our own group to construct the <i>trans</i>-2,6-disubstituted dihydropyran ring, asymmetric α-aminoxylation reaction, and Still–Gennari (<i>Z</i>)-selective olefination reactions. Careful comparison of ¹H and ¹³C NMR spectroscopic data as well as investigation of the UV and circular dichroism spectrum in trifluoroethanol for compound <b>2</b> suggest that the putative structure for diplopyrone {6-[(1<i>S</i>)-1-hydroxyethyl]-2,4a­(<i>S</i>),6­(<i>R</i>),8a­(<i>S</i>)-tetrahydropyran­[3,2-<i>b</i>]­pyran-2-one} requires revision

Total Synthesis of Ivorenolide A Following a Base-Induced Elimination Protocol

A concise and stereocontrolled first total synthesis of Ivorenolide A (<b>1</b>) is reported in 16 longest linear steps with a 13.4% overall yield starting from (+)-diethyl tartrate (DET). Key features are base-induced elimination protocol for the construction of chiral propargyl alcohols in both fragments, Pd-catalyzed cross-coupling of terminal acetylenes, and Shiina’s 2-methyl-6-nitrobenzoic anhydride (MNBA) mediated macrolactonization

Synthesis of Acylsilanes via Nickel-Catalyzed Reactions of α‑Hydroxyallylsilanes

The redox isomerization processes and tandem isomerization–aldolization reactions, mediated by nickel catalysts, offer new versatile entries to acylsilanes. For the second reaction, high diastereoselectivities, up to 98:2, have been obtained with bulky substituents on silicon