Synthesis of 9,10-Diarylanthracenes via Mg(TMP)2·2LiCl-Mediated Benzyne Generation/[4+2] Cycloaddition and Deoxygenation of 9,10-Epoxyanthracene Intermediates

Design of an aryne-platform for the synthesis of non-racemic heterocyclic allocolchicinoids

A four-step semisynthetic approach towards a highly versatile allocolchicine-related chiral aryne intermediate starting from naturally occurring colchicine was developed, and some of its synthetic transformations were studied. The in situ generated benzyne intermediate afforded a number of non-racemic heterocyclic allocolchicinoids, which were shown to exhibit potent cytotoxicity towards COLO 357, OSA and Raji cells. The proposed methodology is attractive for the synthesis of libraries of new cytotoxic tubulin inhibitors.

Epoxyanthracene Derivatives and Dicarbonylation on Benzene Ring via Hexadehydro-Diels–Alder (HDDA) Derived Benzynes with Oxazoles

A capture reaction of hexadehydro-Diels–Alder (HDDA) derived benzyne with various substituted oxazoles is reported. With methyl, hydrogen, or phenyl as the substituent at 2-position of oxazole, tetraynes afforded epoxyanthracene derivatives or underwent dicarbonylation on benzene ring. The reaction does not require any catalyst or additive. The mechanism behind the reaction was investigated. The obtained polycyclic product structure has potential application value in optoelectronic materials. The availability of dicarbonylated arene implies the uniqueness of HDDA benzyne reaction compared with traditional benzyne.

Enantiospecific Generation and Trapping Reactions of Aryne Atropisomers

Enantioenriched aryne atropisomers having a biaryl stereogenic axis vicinal to the reactive triple bond are demonstrated to exist. These reaction intermediates are easily produced in situ and can undergo the standard aryne cycloaddition chemistry in an enantiospecific manner. Notably, the aryne atropisomers herein have allowed the practical syntheses of a small nanographene as well as some triptycene and anthracene derivatives that embed stereogenic axes of controlled absolute configurations.

as-Indaceno[3,2,1,8,7,6-ghijklm]terrylene as a near-infrared absorbing C70-fragment

Carbon and hydrogen are fundamental components of organic molecules and a fascinating plethora of functions can be generated using these two elements. Yet, realizing attractive electronic structures only by using carbon and hydrogen remains challenging. Herein, we report the synthesis and properties of the C₇₀ fragment as-indaceno[3,2,1,8,7,6-ghijklm]terrylene, which exhibits near-infrared (NIR) absorption (up to ca. 1300 nm), even though this molecule consists of only 34 carbon and 14 hydrogen atoms. A remarkably small highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap is confirmed by electrochemical measurement and theoretical calculations. Furthermore, as-indacenoterrylene is stable despite the absence of peripheral substituents, which contrasts with the cases of other NIR-absorbing hydrocarbons such as diradicaloids and antiaromatic molecules. The results of this study thus offer fundamental insights into the design of hydrocarbons with a small band gap.

Copper-mediated 1,2-bis(trifluoromethylation) of arynes

We herein describe an unprecedented 1,2-bis(trifluoromethylation) of arynes with [CuCF3] in the presence of an oxidant DDQ. The method allows the rapid construction of a new class of 1,2-bis(trifluoromethyl)arenes in one-step from aryne precursors under mild conditions. Its synthetic utility has been demonstrated in the preparation of bis(trifluoromethylated) molecules with potential pharmaceutical and materials science applications. Mechanistic studies indicated the presence of an o-trifluoromethyl aryl radical intermediate via CF3 group transfer from [CuCF3] to the aryne.