Intramolecular cycloadditions of photogenerated azaxylylenes provide access to unprecedented polyheterocyclic scaffolds, suitable for subsequent postphotochemical modifications to further grow molecular complexity. Here we explore approaches to rapid "assembly" of novel photoprecursors with nitrogen/oxygen-rich tethers capable of producing potential pharmacophores and also compatible with subsequent 1,3-dipolar cycloadditions to furnish pentacyclic heterocycles with new structural cores, minimal number of rotatable bonds, and a high content of sp hybridized carbons. The modular "assembly" of the photoprecursors and potential variety of postphotochemical modifications of primary photoproducts provide framework for combinatorial implementation of this synthetic strategy.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4527657 | PMC |
http://dx.doi.org/10.1002/ejoc.201403620 | DOI Listing |
Org Lett
February 2023
Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States.
A new mode for complexity-building photochemical cascades which offers experimentally simple transition metal-free intramolecular C-C cross coupling of aromatic amides is attained via an unprecedented [2 + 2] reactivity of ESIPT-generated azaxylylenes. Coupled with short and straightforward postphotochemical modifications of the primary photoproducts, these cascades allow for a significant step-normalized growth of molecular complexity while accessing diverse and complex polyheterocyclic molecular architectures.
View Article and Find Full Text PDFOrg Lett
February 2016
Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States.
Photogenerated aza-o-xylylenes undergo intramolecular cycloaddition reactions to tethered oxazoles, with primary photoproducts featuring a reactive cyclic imine moiety suitable for multicomponent postphotochemical transformations. For example, the reaction of these imine photoproducts with bromoacetyl bromide leads to a key 1,4-dielectrophilic synthon, offering access to diverse polyheterocyclic molecular architectures. This reaction sequence is accompanied by rapid growth complexity in a very few simple synthetic steps, and is in keeping with the philosophy of diversity-oriented synthesis (DOS).
View Article and Find Full Text PDFEuropean J Org Chem
April 2015
Department of Chemistry and Biochemistry, University of Denver, Denver, 80208, USA.
Intramolecular cycloadditions of photogenerated azaxylylenes provide access to unprecedented polyheterocyclic scaffolds, suitable for subsequent postphotochemical modifications to further grow molecular complexity. Here we explore approaches to rapid "assembly" of novel photoprecursors with nitrogen/oxygen-rich tethers capable of producing potential pharmacophores and also compatible with subsequent 1,3-dipolar cycloadditions to furnish pentacyclic heterocycles with new structural cores, minimal number of rotatable bonds, and a high content of sp hybridized carbons. The modular "assembly" of the photoprecursors and potential variety of postphotochemical modifications of primary photoproducts provide framework for combinatorial implementation of this synthetic strategy.
View Article and Find Full Text PDFAust J Chem
July 2015
Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208.
Rapid growth of complexity and unprecedented molecular architectures are realized via the excited-state intramolecular proton transfer (ESIPT) in -acylamidobenzaldehydes and ketones followed by [4+2] or [4+4] cycloadditions with subsequent postphotochemical modifications. The approach is congruent with Diversity-Oriented Synthesis: photoprecursors are synthesized in a modular fashion allowing for up to four diversity inputs. The complexity of the primary photoproducts is further enhanced using straightforward and high-yielding postphotochemical modification steps such as reactions with nitrile oxides, nitrones, Povarov reaction, and oxa-Diels-Alder reaction.
View Article and Find Full Text PDFJ Org Chem
February 2014
Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States.
Modular preassembly of azaxylylene photoprecursors, halogen-substituted in the aromatic ring, their intramolecular [4 + 4] or [4 + 2] cycloadditions to tethered unsaturated pendants, and subsequent postphotochemical capstone modification of the primary photoproducts via Suzuki coupling provides rapid access to diverse biaryls of unprecedented topology. This synthetic sequence allows for rapid growth of molecular complexity and is well aligned with methodology of Diversity-Oriented Synthesis.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!