Professor James R. Vyvyan
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Research Projects
My research interests are in the broad field of organic synthesis and projects in my group range from developing new asymmetric reactions and synthetic methods to the total synthesis of natural products possessing interesting structural features and biological properties. Our work requires detailed analysis of spectra to characterize synthetic intermediates and we frequently use molecular modeling to develop synthetic strategies.
The Heliannuols and Related Compounds: Natural Herbicide Models
The heliannuols (1-11) are a family of natural products isolated in small quantities from the sunflower (Helianthus annuus) that exhibit selective herbicidal activity against other plant species. Efficient synthesis of the heliannuols and simpler structural analogues will allow further studies of their applications in agriculture. In addition to their biological properties, their unusual structures make the heliannuols challenging synthetic targets. Palladium catalyzed coupling of organozinc reagents to aryl halides and vinyl triflates provide the necessary functionality to synthesize all of the heliannuols from a common aromatic core. Our approach to closing the medium ring ether involves phenol epoxide cyclizations. We have recently completed a synthesis of heliannuol D (4) and are now pursuing the other members of this family and related compounds.
Synthesis and Chemistry of Caparratriene
Caparratriene (17) is a sesquiterpene isolated from the large Ocotea caparrapi tree of the Colombian rainforest. Caparratriene has been reported to exhibit surprising activity against leukemia. Furthermore, studies have shown that the activity increases when the cultures are exposed to light and air, suggesting that it is not the parent hydrocarbon, but rather an oxidation product that is responsible for the anti-leukemic activity.
We have published an efficient three-step synthesis of the racemic natural product starting from citronellal. Using this method, we have prepared several compounds with differing substitution of the conjugated diene portion of the molecule. Current and future investigations will focus on the continued preparation of conjugated diene analogues and the reactions of these compounds with respect to photochemistry and oxidation.
The gibbilimbols A-D (21-24) are 4-alkylated phenols isolated in minute quantities from a plant (Piper gibbilimbum) found in the rainforest of New Guinea. These compounds show both antibacterial and anticancer activity.
Napalilactone (25) and pathylactone A (26) are spirolactones isolated from marine sources. The biological activity of these compounds remains unknown, but their unusual and stereochemically complex structures make challenging synthetic targets.
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It is never too early to start reading the literature. |
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Vyvyan group graduates spring 2000. |
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Vyvyan Research Group 1999-2000. Front row, from left: Bevin Parks, Justin Orr, Brady Stillwell, Jenny Oaksmith and Emily Peterson. Back row, from left: Chris Holst, Jim Vyvyan, Allison Johnson, Joe Deverich and Brandon Sherman. Not pictured: Courtney Rubens and Cheryl Schwenk. |
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Allison Johnson (BS 2000) with her Sigma Xi poster. |
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Ryan Looper (BS 1998, MS 1999) hard at work. |
