Benzisoxazole core and benzoxazolopyrrolidine via HDDA-derived benzyne with PTIO/DMPO

A novel method for HDDA-derived benzyne trapped by nitrone was developed. This research described a simple and efficient pathway for the synthesis of benzisoxazoles from arynes and PTIO(2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl), C-C and C-O bonds were formed in a single step without catalyst under mild conditions. The unexpected cleavage of C-N bond contributed to the formation of isoxazole ring, as indicated by DFT studies. Furthermore, we obtained the structure of benzoxazolopyrrolidine when the trapping agent is DMPO(5,5-dimethyl-1-pyrroline N-oxide).

Nickel-Catalyzed Electroreductive Syntheses of Triphenylenes Using ortho-Dihalobenzene-Derived Benzynes

Electrochemical nickel-catalyzed syntheses of triphenylenes by a)reductive trimerization of ortho-dibromobenzenes or ortho-bromoarylsulfurofluoridates,or b)reductive cross-coupling of ortho-dibromobenzenes to 2,2’-diiodobiphenyls,are described.The former provides a practical means for the construction of triphenylene derivatives in up to 87%isolated yield at room temperature.For 1,2-dihalo-3-methylbenzenes and related ortho-trisubstituted substrates,trimerizations proceed with high substrate-controlled regioselectivity for the non-C3h symmetric triphenylene isomer.

Cycloaddition reactions of benzyne with olefins

Some novel cycloaddition reactions based on benzyne and olefins have been developed.These reactions were performed in the absence of a transition metal catalyst,and they displayed good yields.These cycloaddition reactions of benzyne with olefins provide effective routes for synthesizing benzocyclobutenes,biaryl compounds and 9,10-dihydrophenanthrene derivatives.

Synthesis of 9-phenol-substituted xanthenes by cascade O-insertion/1,6-conjugate addition of benzyne with ortho-hydroxyphenyl substituted para-quinone methides

The cascade O-insertion/1,6 conjugate addition between benzynes and ortho-hydroxyphenyl substituted para-quinone methides has been reported, affording 9-phenol substituted xanthenes in 49%-84% yields.

The role of organic electron donors in the initiation of BHAS base-induced coupling reactions between haloarenes and arenes

Coupling reactions between haloarenes and arenes(including heteroarenes)that are conducted without added transition metals but in the presence of KOtBu or NaOtBu,have been a topic of great interest since their discovery in 2008.Diverse organic structures act as additives that assist these reactions.These additives are converted into organic electron donors by the butoxide base and this leads to initiation of the coupling reactions,which proceed by radical chain mechanisms.This review provides an overview of the initiation stages of these reactions.

Synthesis of Potential Inhibitiors for Stat-3 Dimerization

Nine bioactive ochromycinone analogues were synthesized through two different types of routes. Some unexpected products were obtained in the photo-induced oxidation. The syntheses disclosed herein complement those in the literature and offer inexpensive access to many of the known intermediates involved, most of which were studied years ago in completely different contexts.

Fused multifunctionalized bridge aromatic hydrocarbons from in situ-generated arynes and anthracene derivatives

This study presents a facile strategy for the formation of highly substituted butterfly 1,4-adducts/9,10-adducts via the Diels-Alder reaction of benzyne intermediates.The method achieves very good to excellent yields of the respective anthracene derivative s under mild conditions.This practical protocol is compatible with a variety of sensitive functional groups and provides access to difunctionalized bridge 1,4-adducts/9,10-adducts.