First total synthesis of (+)-viroallosecurinine

The first diastereoselective chiral synthesis of (+)-viroallosecurinine, isolated from Securinega virosa as a cytotoxic alkaloid, was achieved by using a chelation-controlled addition of an alkyne moiety to the corresponding ketone, and a ring-closing metathesis, as key reactions.     

New total synthesis of (+)-cystothiazole A based on palladium-catalyzed cyclization-methoxycarbonylation

Palladium-catalyzed cyclization-methoxycarbonylation of (2R,3S)-3-methylpenta-4-yne-1,2-diol (6) derived from (2R,3S)-epoxy butanoate 7 followed by methylation gave the tetrahydro-2-furylidene acetate (−)-10, which was converted to the left-half aldehyde (+)-3. A Wittig reaction between (+)-4 and the phosphoranylide derived from the bithiazole-type phosphonium iodide 4 using lithium bis(trimethylsilyl)amide afforded the (+)-cystothiazole A (2).     

First stereoselective total synthesis of triumfettamide

The first total synthesis of triumfettamide (1) is described. The asymmetric syntheses of two highly functionalized units—α-hydroxylated C17 monounsaturated fatty acid unit (2) and C26 phytosphingosine (3) have been accomplished involving Sharpless asymmetric dihydroxylation, Sharpless kinetic resolution, regioselective epoxide opening, regioselective DIBAL-H reduction of acetal, Wittig olefination as the key steps. Finally N-acylation of phytosphingosine 3 with (2R,6Z)-2-hydroxy-6-heptadecenoic acid 2 followed by DDQ deprotection of PMB, provided target compound 1.     

A practical total synthesis of (+)-isogalbulin and (+)-galbulin

A practical total synthesis of the natural products (+)-isogalbulin and (+)-galbulin has been achieved in 10 steps from readily available 3-(3,4-dimethoxyphenyl)propanoic acid. The total yields were 12.3% and 12.9%, respectively. The key steps involved Evans asymmetric alkylation, Sharpless asymmetric epoxidation, and a highly regioselective opening of 1-benzyloxy-2,3-epoxides with an organoaluminum ate-complex formed by Me₃Al and n-BuLi.     

Stereoselective synthesis of tetrahydroisoquinoline alkaloids: (−)-trolline, (+)-crispin A, (+)-oleracein E

Tetrahydroisoquinoline alkaloids, (S)-(−)-trolline, (R)-(+)-crispin A, and (R)-(+)-oleracein E, have been synthesized stereoselectively from the both enantiomers of common intermediate (S)-4 and (R)-4. The key step in the synthesis include a stereoselective Bi(OTf)₃-catalyzed intramolecular 1,3-chirality transfer reaction of chiral non-racemic amino allylic alcohols (S)-6 and (R)-6 to construct both enantiomers of (E)-1-propenyl tetrahydroisoquinoline 4.     

First stereoselective total synthesis of Phomolide G and H via RCM protocol

A first total synthetic route has been reported for the synthesis of Phomolide G and H. The syntheses of fragments were initiated from commercially available and inexpensive starting material (R)-epichlorohydrin. The synthesis involves a key Sharpless epoxidation, stereoselective epoxide opening, lactonization and ring closing metathesis (RCM).     

A novel concise total synthesis of (+)-lentiginosine

A total synthesis of (+)-lentiginosine was achieved by using ethyl 3-(pyridin-2-yl)acrylate N-oxide as the starting material and an improved Sharpless asymmetric dihydroxylation as the key step.     

First total synthesis of fumaridine

The first total synthesis of the alkaloid fumaridine 1a is reported. The key step is the assemblage of the arylmethylene isoindolinone 2a (E) by Horner reaction between the phosphorylated isoindolinone 3a and the suitably substituted benzaldehyde 4. N-Lactam deprotection and concomitant E→Z isomerization complete the synthesis of the title compound.     

Enantioselective total synthesis of (+)-sarcodictyenone

The first enantioselective total synthesis of (+)-sarcodictyenone is described [4.3% overall yield from (5R,6R)-6-methyl-5-trimethylsily-2-cyclohexenone]. This work establishes the absolute stereochemistry of the natural product.     

Diastereoselective total synthesis of (+)-morusimic acid B, an amino acid from Morus alba

An efficient, flexible and diastereoselective synthesis of the naturally occurring pyrrolidine amino acid, (+)-morusimic acid B, has been accomplished. Starting from chiral, optically active (+)-(3S)-hydroxy butyric acid methyl ester the key steps of our synthesis are diastereoselective α-alkylation of its dianion to introduce the main part of the side chain, Curtius rearrangement of the hydrazide derivative to a 2-oxazolidinone followed by N→π-cyclization with mercury(II) acetate to generate the cis-2,5-disubstituted pyrrolidine ring. The remote C-3 stereocentre is established after chain elongation with the dianion of methyl acetoacetate and asymmetric hydrogenation of the resulting β-oxoester with Noyori's Ru(II)-(R)-BINAP catalyst.     

Stereoselective total synthesis of (+)-varitriol

Stereoselective total synthesis of (+)-varitriol, an antitumor natural product, was accomplished by two versatile strategies starting from the commercially available d-(−)-ribose and ethyl (S)-lactate. The key steps involved in the synthesis of the target molecule are epoxidation, cyclization, dihydroxylation and Diels-Alder reaction.     

First stereoselective total synthesis of decytospolides A and B

The first synthesis of bioactive decytospolides A and B adopting an oxa-Michael addition as the key step is reported.     

Catalytic asymmetric formal total synthesis of (+)-dichroanone and (+)-taiwaniaquinone H

Catalytic asymmetric formal total synthesis of (+)-dichroanone and (+)-taiwaniaquinone H has been achieved. Key step involved construction of all-carbon quaternary carbon by palladium-catalyzed conjugate addition of arylboronic acid to 3-methyl cyclohexenone. Furthermore, a new approach to build [6-5-6] tricyclic backbone via formyl introduction and subsequent aldol-type condensation was also explored.     

First total synthesis of (+)-Carainterol A

The first, stereospecific, and elegant synthesis of the natural product (+)-Carainterol A was developed by using the Robinson annulation reaction as a key step to build the eudesmane sketeton.     

First total synthesis of tripdiolide

The first total synthesis of tripdiolide 1 from the readily available abietic acid 3 in 22 steps is described and this synthesis furnishes a 5.8% overall yield of 1 with an average yield of 87%.     

An efficient synthesis of (+)-prelactone B

An enantioselective synthesis of (+)-prelactone B 1 has been achieved on a multigram scale starting from a known bicyclic precursor 2. The key feature of the strategy is the generation of 3-stereogenic centres from a single bicyclic precursor, which has been utilized as a chiral building block for the synthesis of various natural products.     

First total synthesis of (+)-pentandranoic acid A

The first total synthesis of (+)-pentandranoic acid A (1) was accomplished in 14 steps, starting from alcohol 3. Our synthesis features several key transformations, such as an ozonolysis-aldol cyclization-dehydration ring contraction sequence and a selective 1,4-diol oxidation, and provides an efficient synthetic route to this rare clerodane diterpenoid.     

An enantiospecific synthesis of (+)-hydroxy-exo-brevicomin

A concise enantiospecific synthesis of the pine beetle pheromone (+)-hydroxy-exo-brevicomin was achieved from l-(+)-tartaric acid in high yield. The key step involves the reduction of a keto-Weinreb amide derived from tartaric acid.     

First total synthesis of (+)-hyacinthacine A2

The first synthesis of (+)-hyacinthacine A₂ has been achieved in six steps from 2,3,5-tri-O-benzyl-d-arabinofuranose in an overall yield of 11%. The structure of this natural product was thus unambiguously established as (1R,2R,3R,7aR)-1,2-dihydroxy-3-hydroxymethylpyrrolizidine.     

A total synthesis of (+)-preussin and its 5-epimer

(+)-Preussin (1) and its 5-epimer were synthesized from the divmylcarbmol (3) with Sharpless asymmetric epoxidation of 3 and the oxidative cyclization of 9 with PDC as the key steps