A Bifunctional Lewis Acid Induced Cascade Cyclization to the Tricyclic Core of <i>ent</i>-Kaurenoids and Its Application to the Formal Synthesis of (±)-Platensimycin

A mild and efficient bifunctional Lewis acid induced cascade cyclization reaction has been developed for construction of the tricyclic core of <i>ent</i>-kaurenoids. With ZnBr₂ as the bifunctional Lewis acid, a series of substituted enones and dienes underwent cascade cyclization smoothly at room temperature and provided the tricyclic products in one pot with good yields (75–91%) and high diastereoselectivity. The cyclized product has been successfully employed for the formal synthesis of (±)-platensimycin

A Bifunctional Lewis Acid Induced Cascade Cyclization to the Tricyclic Core of <i>ent</i>-Kaurenoids and Its Application to the Formal Synthesis of (±)-Platensimycin

A mild and efficient bifunctional Lewis acid induced cascade cyclization reaction has been developed for construction of the tricyclic core of <i>ent</i>-kaurenoids. With ZnBr₂ as the bifunctional Lewis acid, a series of substituted enones and dienes underwent cascade cyclization smoothly at room temperature and provided the tricyclic products in one pot with good yields (75–91%) and high diastereoselectivity. The cyclized product has been successfully employed for the formal synthesis of (±)-platensimycin

A Bifunctional Lewis Acid Induced Cascade Cyclization to the Tricyclic Core of <i>ent</i>-Kaurenoids and Its Application to the Formal Synthesis of (±)-Platensimycin

A mild and efficient bifunctional Lewis acid induced cascade cyclization reaction has been developed for construction of the tricyclic core of <i>ent</i>-kaurenoids. With ZnBr₂ as the bifunctional Lewis acid, a series of substituted enones and dienes underwent cascade cyclization smoothly at room temperature and provided the tricyclic products in one pot with good yields (75–91%) and high diastereoselectivity. The cyclized product has been successfully employed for the formal synthesis of (±)-platensimycin

Synthesis of Benzothiazoles by the Reaction of Disulfide and Aromatic Carboxylic Acid Promoted by PCL₃ and DBU

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Bioinspired Total Synthesis of (±)-Yezo’otogirin C

The first and protective group-free total synthesis of (±)-yezo’otogirin C has been achieved from 3-methyl-4-prenylcyclohex-2-enone in eight steps with 23% overall yield. The tricyclic core of (±)-yezo’otogirin C was established via a bioinspired oxidative cascade cyclization strategy using Mn­(II)/Mn­(III) and O₂, followed by reduction of the peroxy-bridged intermediate using thiourea in refluxing methanol

Bioinspired Total Synthesis of (±)-Yezo’otogirin C

The first and protective group-free total synthesis of (±)-yezo’otogirin C has been achieved from 3-methyl-4-prenylcyclohex-2-enone in eight steps with 23% overall yield. The tricyclic core of (±)-yezo’otogirin C was established via a bioinspired oxidative cascade cyclization strategy using Mn­(II)/Mn­(III) and O₂, followed by reduction of the peroxy-bridged intermediate using thiourea in refluxing methanol

Systemic Study on the Biogenic Pathways of Yezo’otogirins: Total Synthesis and Antitumor Activities of (±)-Yezo’otogirin C and Its Structural Analogues

A systematic study of the biomimetic pathways to yezo’otogirin C under aerobic and anaerobic conditions has been investigated, and both are found to be feasible pathways to the natural product depending on the physiological conditions. Because of the lower activation energy, the aerobic process would be more favorable when the in vivo oxygen level is high. In the course of this study, a highly efficient synthetic route to (±)-yezo’otogirin C has been established in four steps (31% overall yield) from a readily available compound without using any protecting groups. The natural product and its structural analogues exhibited antitumor activities against several human cancer cell lines and appeared to arrest cell cycles in different phases

Systemic Study on the Biogenic Pathways of Yezo’otogirins: Total Synthesis and Antitumor Activities of (±)-Yezo’otogirin C and Its Structural Analogues

A systematic study of the biomimetic pathways to yezo’otogirin C under aerobic and anaerobic conditions has been investigated, and both are found to be feasible pathways to the natural product depending on the physiological conditions. Because of the lower activation energy, the aerobic process would be more favorable when the in vivo oxygen level is high. In the course of this study, a highly efficient synthetic route to (±)-yezo’otogirin C has been established in four steps (31% overall yield) from a readily available compound without using any protecting groups. The natural product and its structural analogues exhibited antitumor activities against several human cancer cell lines and appeared to arrest cell cycles in different phases

Enantioselective Synthesis of the ABC-Tricyclic Core of Phomactin A by a γ‑Hydroxylation Strategy

An enantioselective synthesis of the ABC-tricyclic furanochroman core of phomactin A has been accomplished by a γ-hydroxylation approach. The C ring was established by γ-hydroxylation of an α-enone. The regioselectivity was optimized by using a strong base with an oxophilic cation (<i>t-</i>BuLi) and a bulky oxygen donor (Davis reagent), which afforded the γ-hydroxylation product selectively in 63% yield

Light-Controlled Morphologies of Self-Assembled Triarylamine–Fullerene Conjugates

A family of triarylamine–fullerene conjugates has been synthesized and shown to self-assemble upon light stimulation in chlorinated solvents. This light-induced process primarily involves excitation of triarylamine derivatives, which then oxidize and stack with their neutral counterparts to form charge transfer complexes in the form of p-conducting channels, while fullerenes are consequently enforced in coaxial n-conducting columnar arrangements. These supramolecular heterojunctions can be organized over very long distances in micrometric fibers when a controlled amount of photons is provided from a white light source to initiate the process. Surprisingly, when sunlight or UV light is used instead, the nanostructuration leads to monodisperse spherical objects due to the nature of the nucleation–growth process involved in the stacks formation. This control over the supramolecular morphology of organic self-assemblies using the nature of light is of general interest for the design of functional responsive materials