PD-CATALYZED ASYMMETRIC B-HYDRIDE ELIMINATION EN ROUTE TO CHIRAL ALLENES
Ana Maldonado, Kristina Marquez, Ian Crouch.
The University of Texas at San Antonio, San Antonio, TX.
Van ’t Hoff first predicted the unique structure of an allene in 1875. He proposed the composition of 2 C=C bonds connected by an sp hybridized carbon center with the 2 π-systems orthogonal to one another. Today, allenes are no longer hypothetical and have actually been discovered in over 150 natural products such as peridinin and fucoxanthin. In addition, they have been used in commercially available drugs. Due to their unique structure, allenes undergo multiple synthetic transformations. Because of this, they provide a huge incentive to develop synthetic routes to access them. Such routes lack development through the use of catalysts to facilitate enantioselective synthesis of allenes. Since then, several reviews have appeared in literature each containing a few examples of catalytic syntheses. Going through them, it is easy to see that di- and tri- substituted asymmetric allene syntheses have had moderate success with several novel protocols. These results highlight our recent efforts to develop a new route through asymmetric synthesis. [Partially funded by GM060655 and National Science Foundation (CHE-1362953).]