Lyconadin A is an alkaloid possessing a unique structure and antitumor activity. The total synthesis of Lyconadin A was proposed via an acyl radical cascade reaction. To investigate the possibility and stereoselectivity of the cascade cyclization, phenyl selenoester 16 was chosen as a model substrate to study the 7-exo-5-exo radical cyclization. A synthetic route to phenyl selenoester 16 was developed. The 7-exo-5-exo radical cyclization was found to occur with a high yield and excellent stereoselectivty. Attempts were also tried to synthesize another radical precursor 14 albeit with less success. A synthetic pathway to the synthesis of 14 as well as its potential use in the context of the synthesis of Lyconadin A was proposed.

Lyconadin A (1) is a structurally unique Lycopodium alkaloid with antitumor properties, isolated from the club moss Lycopodium complanatum. We are developing a synthetic route to 1 based on a novel 7-exo-trig/6-exo-trig acyl radical cascade cyclization. The synthesis of model acyl radical cascade precursor 23 will be presented. Key features of this synthesis include the suppression of competing elimination during the alkylation of a hindered phenethyl bromide and the use of a lactone as a precursor to a compound bearing two differentially protected primary alcohols. An account of our studies on the model acyl radical cascade cyclization (23 to 24 above) will also be given, including a stereochemical analysis of the product. Our findings have been applied to develop a more detailed stereoselective synthetic plan for Lyconadin A (1).

Lyconadin A is a pentacyclic Lycopodium alkaloid isolated from the club moss Lycopodium companatum with anticancer activity. Our approach sought to incorporate a 7-exo–6-exo acyl radical cyclization cascade to access the bicyclo[5.4.0]undecane framework of lyconadin A. Our studies created methodology for the synthesis of 5-alkyl and 3,5-dialkyl-6-carbomethoxy-2-pyridones and sterically demanding epoxide substrates. These epoxide substrates underwent an unanticipated Payne rearrangement.Cranomycin is a potent antibiotic with antiprotozoal activity. Structurally it is a cyclopentane ring system with substitution at each carbon in the ring. Another interesting structural aspect is the existence of three contiguous quaternary stereocenters including two tertiary alcohols and a tert-alkylamine. Our strategy led to the development of a highly diastereoselective synthesis of vicinal tertiary diol systems. We have successfully synthesized the cyclopentenone system shown above, from which we hope to assemble cranomycin.

This work expands the current understanding of materials chemistry and engineering capabilities of two synthetic platforms: 1.) bis-ortho-diynylarenes (BODA) and 2.) trifluorovinylaryl ethers (TFVE). Each platform possesses a unique chemistry which paradoxically enables the development of high-performance materials therefrom while simultaneously retaining exceptional melt and solution processability. Leveraging the apparent dichotomy in properties (performance/processability) obtainable from these two synthetics platforms, we have pursued and achieved a practical approach to high-temperature resistant materials with an immense potential for technology transfer and commercialization: 1.) BODA-derived resins (BDR) constitute a versatile platform of melt-processable resins capable of rapidly producing high performance matrix composites which include thermoset, carbon-carbon, and other specialty carbon or hybrid ceramic composite structure. BODA monomers can be synthesized via a three-step process from commercially available bisphenols and undergo a facile catalyst-free, thermal-initiated polymerization to yield polyarylene thermosets with outstanding thermal-oxidative stability, low heat release, flame resistance, and high carbon yields (>80%). The combination of melt processability, ease of cure, and high carbon yields in BDR provides an attractive quick, single-step fabrication of carbon/carbon (C/C) composites with excellent interlaminar shear strength (ILSS; ~1800 psi) after a single infusion/carbonization. Furthermore, our work in this area has shown that C/C from BDR can be prepared via a fast carbonization (10 °C/min), relative to typical 1 °C/min or 1 °C/hr industrial carbonizations, without causing undesirable shrinkage, cracking, interlaminar debonding, or detrimental changes in ILSS. 2.) Large polyaromatic hydrocarbons (PAHs) are typically known for their interesting thermal- and photo-optical properties but suffer from poor solubility and processability issues. Functionalization of these moieties with TFVE fluorocarbon groups enables melt or solution polymerization via a thermally initiated [2+2] cyclodimerization of the TFVEs towards high performance perfluorocyclobutyl (PFCB) aryl ether polymers. For example, successful fabrication of free-standing photoluminescent films with record high glass transition temperatures (Tg ~ 300 °C), exceptional thermal-oxidative stability (~250 °C, 24 h), unprecendented photostability at 250 °C in air, and excellent solubility in common organic solvents (at room temperature) have been realized via a set of triphenylene-enchained PFCB aryl ether polymers.

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