Synthesis of cage heterocycles containing tetrahydrofuran and pyran ring systemvia Grignard addition and ring-closing metathesis

Several cage compounds containing tetrahydrofuran and pyran rings have been reported by using the Grignard additionand ring-closing metathesis as key steps. Cage hemiketal derivatives have been generated due to the proximity of twocarbonyl groups in cage dione. These cage heterocycles have been derived from readily available starting materials such as1,4-hydroquinone and dicyclopentadiene

Synthesis of cage heterocycles containing tetrahydrofuran and pyran ring system via Grignard addition and ring-closing metathesis

75-84Several cage compounds containing tetrahydrofuran and pyran rings have been reported by using the Grignard addition and ring-closing metathesis as key steps. Cage hemiketal derivatives have been generated due to the proximity of two carbonyl groups in cage dione. These cage heterocycles have been derived from readily available starting materials such as 1,4-hydroquinone and dicyclopentadiene

Synthesis of cis-syn-cis and cis-anti-cis linear triquinanes via photo-thermal metathesis

1556-1563Diverse cis-syn-cis and cis-anti-cis triquinane frameworks have been assembled by a simple synthetic protocol starting with substituted cage diones under microwave irradiation conditions. Thermal fragmentation of the cyclobutane ring play a key role in this process and milder reaction conditions have been employed in contrast to normal flash vacuum pyrolysis conditions. Here, thermal isomerization of the double bond has also been realized under the microwave irradiation conditions to afford the isomeric triquinanes at low temperature. These triquinane units are considered to be useful for the total synthesis of natural products and non-natural products containing fused cyclopentane rings

Synthesis of cis-syn-cis and cis-anti-cis linear triquinanes via photo-thermal metathesis

Diverse cis-syn-cis and cis-anti-cis triquinane frameworks have been assembled by a simple synthetic protocol starting with substituted cage diones under microwave irradiation conditions. Thermal fragmentation of the cyclobutane ring play a key role in this process and milder reaction conditions have been employed in contrast to normal flash vacuum pyrolysis conditions. Here, thermal isomerization of the double bond has also been realized under the microwave irradiation conditions to afford the isomeric triquinanes at low temperature. These triquinane units are considered to be useful for the total synthesis of natural products and non-natural products containing fused cyclopentane rings

Synthesis of Bisoxazole and Bromo-substituted Aryloxazoles

Herein, we report a bisoxazole derivative as well as a bromo-substituted oxazole derivatives via a simple approach. The synthesis begins with an inexpensive and readily available starting material, such as 2,5-dimethoxybenzaldehyde, hydroquinone, and p-toluenesulfonylmethyl isocyanide (TosMIC). This approach relies on the Van Leusen oxazole method and electrophilic aromatic bromination. The structures of bisoxazole and bromosubstituted aryloxazoles were fully supported by spectroscopic methods (IR, NMR, and HRMS) and further established using single crystal X-ray diffraction studies

Superfast Capture of Iodine from Air, Water, and Organic Solvent by Potential Dithiocarbamate-Based Organic Polymer

Organic polymers are widely explored due to their high stability, scalability, and more facile modification properties. We developed cost-effective dithiocarbamate-based organic polymers synthesized using diamides, carbon disulfide, and diamines to apply for environmental remediation. The sequestration of radioiodine is a serious concern to tackle when dealing with nuclear power for energy requirements. However, many of the current sorbents have the problem of slower adsorption for removing iodine. In this report, we discuss the utilization of an electron-rich dithiocarbamate-based organic polymer for the removal of iodine in a very short time and with high uptake. Our material showed 2.8 g/g uptake of vapor iodine in 1 h, 915.19 mg/g uptake of iodine from cyclohexane within 5 s, 93% removal of saturated iodine from water in 1 min, and 1250 mg/g uptake of triiodide ions from water within 30 s. To the best of our knowledge, the iodine capture was faster than previously observed for any existing material. The material was fully recyclable when applied for up to four cycles. Hence, this dithiocarbamate-based polymer can be a promising system for the fast removal of various forms of iodine and, thus, enhance environmental security

Synthesis of Pentacycloundecane (PCUD) Based Spiro-Pyrano-Cage Framework via Ring-Closing Metathesis

Here, we demonstrate a short synthetic route to pyrano cage systems containing pentacycloundecane units by employing ring-closing metathesis (RCM) as a key step. These cage systems were constructed starting with readily available starting materials by adopting atomic economic processes such as cycloadditions (Diels-Alder reaction and [2+2] cycloaddition), Grignard addition, and olefin metathesis. The key building block, such as hexacyclic cage dione, was prepared from 1,4-naphthoquinone derivative and freshly cracked 1,3-cyclopentadiene. Some of these heterocyclic motifs are useful in biological chemistry and valuable as key synthons for high-energy-density materials

Molecular Acrobatics in Polycyclic Frames: Synthesis of Functionalized <i>D</i>₃‑Trishomocubanes via the Rearrangement Approach

A new synthetic route to <i>D</i>₃-trishomocubanone and oxa- <i>D</i>₃-trishomocubane derivatives has been established by the rearrangement approach. A remotely located methyl substituent in the six-membered ring contributed to the acid-catalyzed rearrangement of the cage dione in an unusual fashion. This rearrangement approach provided an attractive route to extended <i>D</i>₃-trishomocubanes, which are not accessible by the conventional multistep synthetic sequence. For the first time, two phenyl groups were incorporated from the solvent into the strained trishomocubane skeleton in an unprecedented manner via carbocation-mediated rearrangement with the aid of BF₃·OEt₂. Interestingly, an oxa-bridged trishomocubane skeleton was also formed during acid-promoted rearrangement