Formal total synthesis of borrelidin: synthesis of C1-C11 fragment via desymmetrization strategy

A stereoselective formal total synthesis of borrelidin is described. The synthetic strategy for synthesis of C1-C11 fragment features desymmetrization of Diels-Alder adduct, Sharpless asymmetric epoxidation, regioselective opening of chiral epoxide, and alkylation using Evans chiral auxiliary.     

Highly stereoselective approach toward the synthesis of the macrolactone core of amphidinolide W

The diastereoselective synthesis of the macrolactone core of amphidinolide W was successfully accomplished using Evans’ asymmetric alkylation, Aldol reaction, Julia-Kocienski olefination, and Kita’s macrocyclization protocol.     

Stereoselective synthesis of the C3-C15 fragment of callyspongiolide

The synthesis of C3-C15 fragment of callyspongiolide, a 14-membered macrolides isolated from the marine sponge Callyspongia sp., which was collected from the Indonesia, is reported. Highlights of the synthesis include construction of E-olefin through Julia-Kocienski olefination, Brown asymmetric allylation and base-induced elimination reactions for propargyl alcohol synthesis.     

Collective total synthesis of botryanes

The collective total synthesis of a series of botryanes, which are an important group of sesquiterpene antibiotics isolated from the metabolites of the fungus Botrytis cinerea, has been reported. The highly functionalized hydrindane skeleton of the botryanes was efficiently synthesized via an unusual intramolecular Diels-Alder reaction, which was promoted by TsOH as a protic acid. The concise total synthesis of (±)-hypocrolide A with a challenging hexacyclic skeleton was accomplished in 8 steps from the readily available starting materials.     

The first stereoselective total synthesis of the Z-isomer of cytospolide E

A convergent and highly stereoselective total synthesis of the Z-isomer of cytospolide E has been achieved via Evan’s aldol reaction, Sharpless kinetic resolution and RCM cyclisation.     

First total synthesis of 3-aza-11-thia-1,3,5(10)-trieno steroids

The first total synthesis of 3-aza-11-thia-1,3,5(10)-trieno steroids was achieved via an intramolecular Diels-Alder cycloaddition of o-quinodimethanes as the key step.     

Iriomoteolide-1b中C(13)-C(23)片段的立体选择性合成

采用已知文献报道的化合物为起始原料,以不对称Evans-aldol反应和Julia-Kocienski成烯反应为关键步骤,对大环内酯化合物Iriomoteolide-1b的C(13)-C(23)片段结构进行了合成研究.全文使用普通而廉价的原材料或者试剂,采用常规的容易操作的反应条件,实验成本比较低,并且以13步13%的产率得到了C(13)-C(23)片段结构.     

First total synthesis of parvistone C and its C8-epimer

Diastereoselective first total synthesis of parvistone C 1 and C8-epimer 1a are described. The key features of our synthesis include Sharpless asymmetric dihydroxylation, stereoselective aryl Grignard reactions, Still–Gennari olefination, and intramolecular cyclization.     

Studies toward the total synthesis of gambieric acids, potent antifungal polycyclic ethers: convergent synthesis of a fully elaborated GHIJ-ring fragment

A stereocontrolled synthesis of a fully elaborated GHIJ-ring fragment of gambieric acids, which are potent antifungal polycyclic ether natural products, has been accomplished. The synthesis features convergent assembly of the tetracyclic polyether skeleton through aldol coupling/cyclodehydration/reductive etherification processes and stereoselective construction of the J-ring side chain by a CeCl₃-promoted Julia-Kocienski olefination.     

A stereoselective total synthesis of (±)-tormesol

A general strategy for the synthesis of both trans/syn- and trans/anti-sphenolobane diterpenes has been developed, which utilizes an intramolecular ester enolate alkylation (IEEA) as a key step. A stereoselective total synthesis of (±)-tormesol (1), an unusual trans/syn-sphenolobane diterpene, was accomplished in 18 steps in 4.1% overall yield from readily available aldehyde 16.     

First total synthesis of 11-selena steroids

The first total synthesis of 11-selena steroids was achieved via an intramolecular Diels-Alder cycloaddition of o-quinodimethanes as the key step.     

The first stereoselective and the total synthesis of Leiocarpin C and total synthesis of (+)-Goniodiol

The synthesis of the styryl lactone Leiocarpin C has been achieved in a highly stereoselective manner using Jacobsen’s kinetic resolution, Sharpless asymmetric epoxidation and Sharpless asymmetric dihydroxylation as key steps. This is the first total synthesis of Leiocarpin C, and thus establishes for the first time the absolute stereochemistry of this natural product.     

Angular hydroxymethyl directed intramolecular Diels-Alder approach for the stereo- and regioselective synthesis of pimaraditerpenes

The stereo- and regioselective synthetic route to pimaraditerpenes, employing an angular hydroxymethyl directed intramolecular Diels-Alder reaction of the decaline intermediate, has been developed. This synthetic approach allows prompt access to both natural pimaraditerpenes and the unnatural regioisomers, which would be potentially new anti-inflammatory pimaraditerpenes.     

First total synthesis of 11-tellura steroids

The first total synthesis of 11-tellura steroids was achieved via an intramolecular Diels-Alder cycloaddition of o-quinodimethanes as the key step.     

An improved stereoselective total synthesis of (R)-rugulactone

A novel route for the stereoselective total synthesis of (R)-rugulactone 1 has been developed, starting from substituted epoxide 4 and 3-phenylpropionaldehyde 5 employing Julia-Kocienski olefination as a key step to construct E-configured α,β-unsaturated keto-group. The overall yield of the synthesized rugulactone is 19.94% and is better than the reported methods.     

Synthetic studies of GKK1032s: the asymmetric synthesis of the decahydrofluorene skeleton via a novel cyclization of silyl enol ether and sequential retro Diels-Alder and intramolecular Diels-Alder reactions

GKK1032s, which were isolated from the culture broth of Penicillium sp. GKK1032, exhibit antitumor activity. We constructed the fully elaborated decahydrofluorene skeleton of GKK1032s. The C-ring was constructed by intramolecular cyclization reaction between a chiral epoxide and silyl enol ether, and the dienophile moiety was introduced concurrently. In addition, the AB-rings were stereoselectively constructed using novel sequential retro Diels-Alder (DA) and intramolecular Diels-Alder (IMDA) reactions. Several further modifications of the IMDA adduct were carried out, leading to the asymmetric synthesis of the desired hydroxyester including nine stereo centers.     

A total synthesis of 11-O-methyldebenzoyltashironin

A concise total synthesis of 11-O-methyldebenzoyltashironin is reported in which oxidative dearomatization-IMDA-RCM triad constitutes the key ring forming steps, while an unorthodox DIBAL-H mediated stereo- and regioselective reductive epoxide openings and implementation of the vinyl bromide-carbonyl equivalency concept were pivotal to the success of this endeavor.     

A stereoselective total synthesis of (−)-seychellene

A stereoselective total synthesis of the tricyclic sesquiterpene (−)-seychellene, starting from (R)-carvone via (R)-3-methylcarvone has been accomplished, employing a combination of intermolecular Michael addition-intramolecular Michael addition sequence, a stereoselective hydrogenation, and an intramolecular alkylation reaction.     

Strategic innovations for the synthesis of vinigrol

Since the isolation of unique tricyclic diterpenoid vinigrol, its promising biological activities and complex framework have resulted in numerous synthetic efforts to the total synthesis of this venerable molecule for the past two and half decades. This mini review highlights the significance of various synthetic strategies towards this structurally unique and challenging natural product.