Nessan Kerrigan is the newest member of the CBR

Nessan Kerrigan is newest member of the CBR

 

Nessan Kerrigan, of the Department of Chemistry, has been appointed a member of the Center for Biomedical Research. Kerrigan currently holds grants from the National Institutes of Health and the National Science Foundation, and is publishing regularly in scientific journals. For example, his paper with graduate student Shi Chen appeared in the Journal of Organic Chemistry (Phosphine-Catalyzed Asymmetric Synthesis of beta-Lactones from Disubstituted Ketenes and Aldehydes, Volume 79, Pages 4920-4929, 2014). The abstract is given below.

 

In this article we describe a general catalytic procedure for the formation of beta-lactones bearing two stereogenic centers, from disubstituted ketenes and achiral aldehydes. BINAPHANE was found to display excellent enantioselectivity (>= 90% ee for eight examples) and good diastereoselectivity (>= 90:10 for 13 examples) in catalyzing the formation of beta-lactones bearing two stereogenic centers from achiral aldehydes (both aromatic and aliphatic) and alkylarylketenes or dialkylketenes. A preference for formation of the trans diastereomer was observed in these reactions. For those reactions where BINAPHANE failed as a catalyst, tri-n-butylphosphine was found to be an effective achiral nucleophilic catalyst, effecting good yield and diastereoselectivity in racemic beta-lactone formation. Evidence for the involvement of phosphonium enolate intermediates in the reaction mechanism was obtained through reaction monitoring by P-31 NMR spectroscopy and by comparison with previously characterized intermediates observed in the phosphine-catalyzed ketene homodimerization reaction.


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