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Ring-Opening Benzannulations of Cyclopropenes, Alkylidene Cyclopropanes, and 2,3-Dihydrofuran Acetals: A complementary Approach to Benzo-fused (Hetero)aromatics

Over the past decades, functional group manipulation of aromatic precursors has been a common strategy to access new aromatic compounds. However, these classical methods, such as Friedel-Crafts alkylations and electrophilic/nucleophilic aromatic substitutions, have shown lack of regioselectivity besides the use of activators in excess amounts. To this end, numerous benzannulations to form benzo-fused substrates via Diels-Alder (DA), ring-closing metathesis (RCM), cycloaddition, and transition-metal-promoted processes have been reported. Appending a benzene ring directly onto a pre-existing ring is preferable to many classical methods due to the likely reduction of reaction steps and superior regiocontrol. However, many of these benzannulation reactions require air- and/or moisture- sensitive reaction conditions, a last oxidation step, or the use of highly functionalized precursors. Here we disclose three ‘complementary’ intramolecular ring-opening benzannulations to access a large array of functionalized (hetero)aromatic scaffolds utilizing cyclopropenes-3,3-dicarbonyls, alkylidene cyclopropanes-1,1-diesters, and 2,3-dihydrofuran O,O- and N,O- acetals as building blocks. More than 70 benzo-fused aromatic compounds were synthesized using this complementary approach with yields up to 98% and low catalyst loadings. With these benzannulation reactions in hand, we aim to open the synthetic door to a handful of bioactive natural products.

Identiferoai:union.ndltd.org:GATECH/oai:smartech.gatech.edu:1853/54916
Date27 May 2016
CreatorsAponte-Guzman, Joel
ContributorsFrance, Stefan
PublisherGeorgia Institute of Technology
Source SetsGeorgia Tech Electronic Thesis and Dissertation Archive
Languageen_US
Detected LanguageEnglish
TypeDissertation
Formatapplication/pdf

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