Enantioselective Total Syntheses of (−)‐Rhazinilam, (−)‐Leucomidine B,and (+)‐Leuconodine F

A divergent total synthesis of three structurally distinct natural products from imine 9 was accomplished through an approach featuring: 1) a Pd‐catalyzed decarboxylative cross‐coupling, and 2) heteroannulation of 9 with bromoacetaldehyde and oxalyl chloride to give tetrahydroindolizine 6 and dioxopyrrole 7 , respectively. The former was converted into (−)‐rhazinilam, while the latter was converted into (−)‐leucomidine B and (+)‐leuconodine F. A substrate‐directed highly diastereoselective reduction of a sterically unbiased double bond by using a homogeneous palladium catalyst was developed. A self‐induced diastereomeric anisochronism (SIDA) phenomenon was observed for leucomidine B.     

A General Entry to Antifeedant Sesterterpenoids: Total Synthesis of (+)‐Norleucosceptroid A, (−)‐Norleucosceptroid B,and (−)‐Leucosceptroid K

The first asymmetric total synthesis of the antifeedant terpenoids (+)‐norleucosceptroid A, (−)‐norleucosceptroid B, and (−)‐leucosceptroid K has been accomplished. This highly concise synthetic route was guided by our efforts to develop a platform for the collective synthesis of a whole family of antifeedant natural products. The synthesis features a Hauser–Kraus‐type annulation followed by an unprecedented, highly efficient intramolecular dilactol aldol‐type condensation reaction to produce the 5,6,5 skeleton. The developed synthetic route proceeds for norleucosceptroid A and B in 16 steps (longest linear sequence) from known compounds.     

Total Synthesis of (−)‐Haouamine B Pentaacetate and Structural Revision of Haouamine B

The enantiocontrolled total synthesis of (?)‐haouamine B pentaacetate was accomplished via an optically active indane‐fused β‐lactam, which was prepared by a newly developed Friedel–Crafts reaction. Subsequent cleavage of the β‐lactam and an intramolecular McMurry coupling reaction provided the core indane‐fused tetrahydropyridine, which led to the elucidation of the structure, as proposed by Trauner and Zubía.     

Unified Total Syntheses of (−)‐Medicarpin, (−)‐Sophoracarpan A,and (±)‐Kushecarpin A with Some Structural Revisions

The total syntheses of medicarpin, sophoracarpan A, and kushecarpin A from a common intermediate are achieved by using ortho‐ and para‐quinone methide chemistry. Additionally, the relative stereochemistry of sophoracarpan A and B have been reassigned.     

Short and Divergent Total Synthesis of (+)‐Machaeriol B, (+)‐Machaeriol D, (+)‐Δ8‐THC,and Analogues

Short and highly efficient stereoselective syntheses provide machaeriols and cannabinoids in a divergent approach starting from a common precursor, commercially available (S)‐perillic acid. Key features of the novel strategy are a stereospecific palladium‐catalyzed decarboxylative arylation and a one‐pot sequence comprising a stereoselective hydroboration followed by oxidation or reduction of the corresponding intermediary boranes. The divergent approach is convincingly demonstrated by the five‐step syntheses of (+)‐machaeriol B, (+)‐machaeriol D, and related analogues, and the four‐step synthesis of (+)‐Δ⁸‐THC and an analogue.     

Convergent Total Syntheses of (−)‐Rubriflordilactone B and (−)‐pseudo‐Rubriflordilactone B

A highly convergent strategy for the synthesis of the natural product (?)‐rubriflordilactone B, and the proposed structure of (?)‐pseudo‐rubriflordilactone B, is described. Late stage coupling of diynes containing the respective natural product FG rings with a common AB ring aldehyde precedes rhodium‐catalyzed [2+2+2] alkyne cyclotrimerization to form the natural product skeleton, with the syntheses completed in just one further operation. This work resolves the uncertainty surrounding the identity of pseudo‐rubriflordilactone B and provides a robust platform for further synthetic and biological investigations.     

Enantioselective Total Synthesis of (−)‐Lansai B and (+)‐Nocardioazines A and B

The concise total syntheses of the bis(pyrroloindolines) (?)‐lansai B and (+)‐ nocardioazines A and B are reported. The key pyrroloindoline building blocks are rapidly prepared by enantioselective formal [3+2] cycloaddition reactions. The macrocycle of (+)‐nocardioazine A is constructed by an unusual intramolecular diketopiperazine formation.     

Enantioselective Total Syntheses of (−)‐Rhazinilam, (−)‐Leucomidine B,and (+)‐Leuconodine F

A divergent total synthesis of three structurally distinct natural products from imine 9 was accomplished through an approach featuring: 1) a Pd‐catalyzed decarboxylative cross‐coupling, and 2) heteroannulation of 9 with bromoacetaldehyde and oxalyl chloride to give tetrahydroindolizine 6 and dioxopyrrole 7 , respectively. The former was converted into (?)‐rhazinilam, while the latter was converted into (?)‐leucomidine B and (+)‐leuconodine F. A substrate‐directed highly diastereoselective reduction of a sterically unbiased double bond by using a homogeneous palladium catalyst was developed. A self‐induced diastereomeric anisochronism (SIDA) phenomenon was observed for leucomidine B.     

Total Synthesis of (±)‐Clavilactones A,B, and Proposed D through Iron‐Catalyzed Carbonylation–Peroxidation of Olefin

Biologically significant clavilactones A, B, and the previously proposed D have been synthesized through iron‐catalyzed carbonylation–peroxidation of a 1,5‐diene. Three steps from aldehydes, alkenes, and tert‐butylhydroperoxide build up α,β‐epoxy‐γ‐butyrolactone skeleton as a key building block for synthesis of clavilactone family and its derivatives. Based on our results, the structure of the proposed clavilactone D is not correct and requires revision.