Asymmetric Total Synthesis of Naphthospironone A

Naphthospironone A, a polyhydroxy cagelike bioactive natural product, was synthesised for the first time in this study. The spiro[bicyclo[3.2.1]octane-pyran] core was constructed by an acid-promoted epoxide-opening lactonisation and a base-induced intramolecular aldol-type cyclisation.     

Asymmetric Total Synthesis of Hispidanin A

Asymmetric total synthesis of the dimeric diterpenoid hispidanin A was accomplished by non-catalytic Diels–Alder cycloaddition at room temperature. The synthesis relies on iron-catalyzed coupling to construct a Z-configured trisubstituted alkene, an iron-catalyzed radical cascade to generate a labdane-type diene, and both Yamamoto cationic polyene cyclization and palladium-catalyzed Stille coupling to generate a totarane-type dienophile.     

Asymmetric Total Synthesis of Fredericamycin A

Seventeen years after the isolation of the promising antitumor antibiotic fredericamycin A, the first asymmetric total synthesis of this compound has been accomplished and thereby its absolute configuration established. The key feature is the regiocontrolled [4+2] cycloaddition of 3 to 2 , which was obtained by the stereospecific rearrangement of 1 . Cp = (−)‐camphanoyl.     

The First Total Synthesis of the Diastereoisomers A and B of Tuxpanolide from Perymenium hintonii

The first total synthesis of the diastereoisomers A and B of the natural product Tuxpanolide have been achieved through the stereo‐controlled construction of optically active β‐hydroxyl‐γ‐butyrolactones, the aldol coupling, dehydration and deprotection reaction with the p‐TsOH as the key steps.     

Catalytic Asymmetric Total Synthesis of Leucinostatin A

This review describes our efforts toward achieving catalytic asymmetric total synthesis of leucinostatin A, a compound that interferes with the tumor‐stroma interaction. The synthesis utilizes four catalytic asymmetric reactions, including direct‐type reactions exemplified by high atom‐economy, and three C?C bond forming reactions. Thorough analysis of the NMR data, HPLC profiles, and biologic activity led us to unambiguously revise the absolute configuration regarding the 6‐position of the AHMOD residue side chain from S (reported) to R. Other examples of previously reported important studies on the stereoselective synthesis of HyLeu and AHMOD are also described.     

Isolation and Asymmetric Total Synthesis of Perforanoid A

A novel limonoid, perforanoid A, was isolated, and an asymmetric total synthesis was achieved in 10 steps. The key steps are chiral tertiary aminonaphthol mediated enantioselective alkenylation of an aldehyde to an allylic alcohol, Pd‐catalyzed coupling of the allylic alcohol with vinyl ether to form the γ‐lactone ring, and cyclopentenone ring formation through a Rh‐catalyzed Pauson–Khand reaction. Preliminary studies show that perforanoid A is cytotoxic towards HEL, K562, and CB3 tumor cell lines.     

A Novel Asymmetric Total Synthesis of (+)-Artemisinin

A 12-step synthesis of the natural product (+)-Artemisinin, very active against malaria, is described. (-)-Isopulegol, which already contains two of the asymmetric centers of (+)-Artemisinin in the correct absolute configuration, was used as starting material.     

Asymmetric Total Synthesis of Mycoleptodiscin A

The first total synthesis of mycoleptodiscin A, a structurally unusual indolosesquiterpenoid possessing an ortho‐benzoquinone motif, has been accomplished. A sulfone alkylation coupled two readily available fragments to give an aryl triene intermediate. The tetracyclic core of the molecule was assembled through a highly enantioselective iridium‐catalyzed polyene cyclization. The benzylic homologation was achieved by a cationic cyanation. The indole motif was constructed via a copper‐mediated intramolecular C? N bond formation at a late stage.     

Asymmetric Total Synthesis of Fluvirucinine A(1)

Diastereoselective vinyl addition to an amide carbonyl group and amide enolate induced aza-Claisen rearrangement are the key steps in the first asymmetric total synthesis of fluvirucinine A(1) (1), the aglycon of fluvirucin A(1). Fluvirucins are a class of macrolactam antibiotics produced by actinomycete strains that show promising biological properties.     

Catalytic Asymmetric Total Synthesis of Exiguolide

The catalytic asymmetric total synthesis of (−)-exiguolide, a complex 20-membered macrolide embedded with a bis(tetrahydropyran) motif, is reported. The convergent synthesis involves the construction of the C1–C11 tetrahydropyran segment via catalytic asymmetric allylation and Prins cyclization, and the formation of the C12–C21 phosphonate segment via catalytic asymmetric cyclocondensation reaction and Johnson–Claisen rearrangement. The synthesis of 15-epi-exiguolide is also described.     

Asymmetric Total Synthesis of Stagonolide F

A highly convergent stereoselective total synthesis of stagonolide F is described starting from commercially available 5-hexen 1-ol using asymmetric dihydroxylation, Jacobsen^'s hydrolytic kinetic resolution (HKR), regioselective epoxide ring opening with vinyl Grignard reaction, esterification, and ring-closing metathesis (RCM) as key steps.     

Asymmetric Total Synthesis of Stagonolide G

A simple asymmetric total synthesis of stagonolide G ( 1 ) is described. Asymmetric dihydroxylation, regioselective epoxide ring opening, and vinyl Grignard reactions are involved in generating the stereogenic centers C(4) and C(8), followed by Grubbs‐II‐catalyzed ring‐closing metathesis (RCM).     

Enantioselective Total Synthesis of Epothilone A Using Multifunctional Asymmetric Catalyses

A catalytic version has now been developed for the enantioselective total synthesis of epothilone A (1). The key is the use of multifunctional asymmetric catalyses for a direct aldol reaction and cyanosilylation. This successful approach demonstrated the usefulness of these reactions for the catalytic asymmetric synthesis of complex molecules.     

A Total,Asymmetric Synthesis of 2-Deoxy-L-fucose from Furan

Abstract

The Diels-Alder adduct (+)?1 of furan to 1-cyanovinyl (1′S)-campha-nate was converted to methyl 3,5-O-diacetyl-2,6-deoxy-β-L-lyxo-hexofurano-side ((+)?12), a protected form of 2-deoxy-L-fucose, in 8 steps and 16.6% overall yield.     

Divergent Asymmetric Total Synthesis of Mulinane Diterpenoids

A concise, divergent, asymmetric total syntheses of mulinane diterpenoids has been achieved. Specifically, a new strategy was developed featuring a key intramolecular Friedel–Crafts reaction to construct the chiral fused 5‐6‐6 tricyclic motif, followed by sequential Birch reduction, conjugate methylation, and homologation/ring‐expansion reactions to furnish the desired 5‐6‐7 tricyclic skeleton bearing five contiguous stereocenters. With this efficient strategy, seven mulinane diterpenoids and two analogues were synthesized via late‐stage functional modification or functionalization in 8.6–20 % overall yields and 11–15 steps.