Metathesis-based synthesis of 3-methoxy α,β-unsaturated lactones: total synthesis of (R)-kavain and of the C1-C6 fragment of jerangolid D

The total synthesis of (R)-kavain and of the C1-C6 fragment of jerangolid D has been achieved in nine and seven steps, respectively, from commercially available dimethyl d-malate. A metathesis reaction of vinyl ethers and a sulfoxide-modified Julia olefination have been employed as the key steps.     

Efficient synthesis of bongkrekic acid. Three-component convergent strategy

An efficient total synthesis of the apoptosis inhibitor bongkrekic acid was accomplished using a three-component convergent strategy involving a Kocienski-Julia olefination and a Suzuki-Miyaura coupling, in which the longest linear sequence was 18 steps and proceeded in 6.4% overall yield. The torquoselective olefination also contributed to the shortening of the synthesis.     

Total synthesis of the alkaloid (−)-codonopsinine from l-xylose

The enantiopure total synthesis of (−)-codonopsinine is described from commercially available l-xylose in 20% overall yield. The key steps included Julia trans olefination and cascade epoxidation-cyclisation strategies.     

Synthesis of moenocinol and its analogs using BT-sulfone in Julia-Kocienski olefination

Moenocinol (C₂₅H₄₂O), the acyclic terpenoid unsaturated lipid part of moenomycin antibiotics, was prepared by an expedient method, which comprised organometallic reaction, Julia-Kocienski olefination, and enolate carbon bond formation as the key steps. The starting materials, nerol and 3-butyn-1-ol, were elaborated to the benzothiazole sulfone 2 and aldehyde 3, and the subsequent Julia-Kocienski olefination occurred in a stereospecific manner to give the desired 6E-configuration of moenocinol. Moenocinol (1) was thus synthesized by 10 linear steps in 12% overall yield, and its analogs 23, 24, and 28 with different chain lengths and unsaturation degrees were also realized by the similar reaction sequences.     

Total synthesis of Carpatamides A–D

A synthetic strategy was developed for the synthesis of the common core structure of Carpatamides A–D. The total synthesis of Carpatamides A and C was completed in 6 steps and of Carpatamides B and D in 7 steps, by employing the Wittig olefination, olefin cross metathesis and acid amine coupling reactions as key steps.     

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.     

Stereoselective Total Synthesis of Oxylipins: (6S,7E,9R,10S)‐6,9,10‐Trihydroxyoctadec‐7‐enoic Acid and (6Z,8R,9R,10S)‐8,9,10‐Trihydroxyoctadec‐6‐enoic Acid

The stereoselective total syntheses of oxylipins 1b and 1c are described starting from readily accessible natural sugars via the Grubbs cross‐metathesis, Wittig olefination, and Zn‐mediated reductive elimination as key steps.     

Stereoselective synthesis of (+)-radicamine B

A simple and efficient stereoselective synthesis of naturally occurring pyrrolidine alkaloid, radicamine B has been accomplished in 13 steps from the commercially available starting materials with an overall yield of 9.75%. The synthesis utilizes Sharpless asymmetric epoxidation and Horner-Wadsworth-Emmons (HWE) olefination as key steps.     

Modified Julia olefination and α aminoxylation reactions mediated convergent synthesis of 1α, 24 (R)-dihydroxyvitamin D3 (tacalcitol)

A convergent synthesis of tacalcitol has been achieved starting from inexpensive and commercially available isovaleraldehyde and easily available Inhoffen-Lythgoe diol. Key steps include a proline catalyzed α aminoxylation and a Julia-Kocienski olefination.     

An efficient stereoselective synthesis of (+)-deoxoprosophylline

An efficient stereoselective synthesis of (+)-deoxoprosophylline from readily available p-anisaldehyde is described. Key steps in the synthesis include the stereoselective amination of anti-1,2-dibenzyl ether using chlorosulfonyl isocyanate, intermolecular olefination, and Pd-catalyzed intramolecular cyclization.     

Preparation of 9,13-dicis double bonds locked retinoids

Synthesis of two retionids in which the 9, 13-dicis double bonds were locked in cycloalkene or thiophene was described. The key steps were the Wittig olefination of phosphonium salt 3 and 23 with aldehyde 14, followed by carbonylation of vinyl bromide 17 and 24 with carbon monoxide in the presence ofPd(PPh3)4.     

Stereoselective Total Synthesis of Stagonolide E

An efficient and highly stereoselective synthesis of stagonolide E ( 1 ) starting from the readily available hexane‐1,6‐diol ( 8 ) was accomplished, employing MacMillan α‐hydroxylation, Horner? Wadsworth? Emmons olefination, (Z)‐selective Still? Gennari olefination, and Yamaguchi lactonization as key steps.     

Stereoselective synthesis of Certonardolsterol D3

The first stereoselective synthesis of Certonardolsterol D₃ was described. Ene reaction and improved allylic oxidation were employed as key steps for efficient construction of the desired 3β,6α,15β-triol steroidal framework. The chiral side chain in Certonardolsterol D₃ was finally introduced by Julia olefination.     

Synthesis of chalcones and flavanones using Julia-Kocienski olefination

A new application of Julia-Kocienski olefination for the synthesis of chalcones and flavanones has been described. 2-(Benzo[d]thiazol-2-ylsulfonyl)-1-phenylethanones have been developed as new reagents for direct Julia-Kocienski olefination with aldehydes in the presence of a base, afforded chalcones in good to excellent yields. Whereas, 2-(benzo[d]thiazol-2-ylsulfonyl)-1-(2-hydroxyphenyl)ethanone reacted with the aromatic aldehydes to furnish flavanones in good yields via one-pot intra-molecular cyclization.     

An efficient approach for the total synthesis of balticolid

An efficient stereoselective total synthesis of balticolid has been accomplished starting from known aldehyde. The key steps involved in this synthesis are Sharpless asymmetric epoxidation, Wittig olefination, alkylation of 1,3-dithiane and Yamaguchi macrolactonization.     

Total syntheses of bupleurynol and its analog

An efficient route to the natural products bupleurynol and its analog (RB-2), isolated from Bupleuri Radix, was established based on versatile intermediate (15). In this synthetic route, Sonogashira and Cadiot-Chodkiewicz coupling as well as Julia-Kocienski olefination are utilized as key steps. The highly efficient synthetic route provides opportunities to explore the biological behavior of bupleurynol and RB-2.     

Progress towards the total synthesis of 2,3-dihydroxytrinervitanes

Intramolecular Diels-Alder approach to construct the fused AB ring of trinervitane has been demonstrated efficiently. The key intermediate for the Diels-Alder cyclization has been achieved following highly stereoselective Julia-Kocienski olefination, Sharpless epoxidation and Evan’s asymmetric alkylation as the key reactions.     

ReO3(bipy)]+[X]--catalyzed aldehyde olefination: carbene and phosphorane intermediates

The aldehyde olefination reaction, catalyzed by cationic high-valent oxorhenium complexes, shows evidence of the intermediacy of both carbene complexes and phosphoranes. The solution-phase reaction is facile and amenable to tuning and is, hence, likely to prove to be of practical significance. Individual steps in the catalytic cycle are observed in the gas phase. Catalytic competence of each of the putative intermediates can be demonstrated.     

Total Synthesis of Codeine

In this paper, a new strategy towards the synthesis of codeine and morphine is reported. This new approach features a cascade cyclization to construct the dihydrofuran ring, and an intramolecular palladium catalyzed C?H olefination of unactivated aliphatic alkene to install the morphinan ring system.     

A Chiron Approach for the Total Synthesis of Crassalactone A

The total synthesis of crassalactone A ( 1 ) has been achieved in twelve steps starting from commercially available 1,5‐D ‐gluconolactone. Still? Gennari olefination, one‐pot deprotection, and lactonization are the key reactions involved in the synthesis.